Your home digital assistant is always listening. But is it always offering you the best content, the cheapest deals, and the right search results?

Digital assistant devices such as Alexa, Google Home, Siri and Cortana are increasingly prevalent. These devices listen for every command, their platforms know where you are, and they have a deep and evolving understanding of your preferences.

But there’s a catch. The device can only provide one answer to each question, and that answer will almost certainly be the one that keeps you in the device’s ecosystem.

Each of the major platforms, known as FAANG (for Facebook, Amazon, Apple, Netflix and Google), has its own ecosystem, and advertising revenue is maximised for the platform when a user stays within it. So while personal digital assistants might be helpful, that help is likely to be limited.

Shopping around is difficult

More than one in five people who own a smart speaker now say they shop via voice commands.

So what happens when you request a price for a particular product? It probably won’t come as a surprise to learn that if you’re asking Alexa, the assistant will usually offer the price that’s available on Amazon. After all, Alexa is an Amazon product, and Amazon promotes this feature.

Apple’s assistant Siri, on the other hand, will use two pieces of information: the product that you requested, and websites that have pricing. So Siri might suggest Amazon, but it’s unlikely that Alexa will suggest Apple, unless you ask for an Apple product. That means, depending on your device, Siri may offer more options.

At the moment, a Google Home Hub doesn’t allow you to shop, even though Google Shopping, which is accessible online, does.

Smart home devices aren’t always compatible

Digital assistants can also help you automate smart devices in your home, which can help minimise energy bills. But here too, you might be restricted by your chosen assistant.

At the moment, most Wi-Fi light globes can be controlled by any of the ecosystems. But as these smart devices become more prevalent, there is a risk that they will be controllable only by one type of assistant.

The smart home manufacturing company Nest, which is owned by Google’s parent, Alphabet, has some devices that can be managed by Alexa and Siri. For example, Nest thermostats and cameras can be controlled by Alexa. The Nest alarm system, however, is linked to Google Home.

This is an area where there is a risk of “tipping”. That is, where a market leader becomes the preferred provider. Once that happens, products like smart globes no longer need to be compatible with multiple ecosystems, and can be designed to work only with the dominant player. That choice is made by the smart globe manufacturer, not by consumers. `

What your assistant knows about you

While compatibility and getting a good deal are both important, so is your privacy.

All digital assistants listen all of the time. They are listening out for the words that trigger an activity (such as “Hey, Google”). It’s important to recognise that the assistants don’t actually understand the questions that they are asked. Instead, they capture audio and provide the best response to their representation of that audio. This means that assistants are not really listening to your every word. The Alexa app will tell you what Alexa has heard and responded to.

It’s also worth noting that the assistant probably knows when you’re not home. This awareness might flow from you actually telling the assistant that you are off to work, but it’s also available from other parts of the ecosystem.

For example, if you provide your location to use Google maps, your Google Home device will know you’re not at home and that it doesn’t need to listen for your instructions. It may also mean that the advertisements that you are served reflect the fact that you’re on the move.

Weighing up the options

Once you’ve figured out what each assistant might know about you via related products, the next step is deciding on the ecosystem.

As we’ve seen, each personal assistant reinforces a specific infrastructure. For example, Alexa has aligned with Sonos for playback hardware, and you cannot currently control Sonos through Google Home.

As a consumer, you get to decide whether the limitations that leave you in a single ecosystem are worthwhile for the convenience offered. The most important question here is whether anyone is informed enough to be able to make that call.

If you really want to know the limitations of your digital assistant, one logical way of learning that might be to ask it. But if you ask a range of assistants what their terms and conditions of service are, you get answers like:

I’m sorry, I’m not sure about that.

I can’t help you with that right now, but my team is working on it.

I don’t really like talking about myself.

Choosing whether to use a home personal assistant means making a choice about privacy. It also means deciding which ecosystem will best meet your needs. Unfortunately, the assistant itself will not help you much in discovering the limitations of the service that you have chosen.