Battery-powered switch - what is the battery used for in modern switches?

Hi.
The last time I bought a switch it was somewhere around 10 years ago, now I want to buy one from the same company but I'm puzzled by the battery power in the description, my old switches from this company don't have any batteries, what is the battery for?

Since there is a radio module in it (433MHz), this means that a power supply, for example from a battery, is necessary for operation. That is, to answer your question directly - the battery is used to power the communication module.

They don't make any other single channel ones now, just with a battery?
I'm looking for a single channel and all I see are with this battery.

I wonder how long this CR2032 will last.
Since it can be overridden remotely, I guess the RF module must be active all the time and listening to what's going on in the circle?

@Karachan
There is just a lot of negative feedback about the battery dying quickly.
I have two Smart Sonoff switches at home bought 10 years ago and they didn't have this battery.
Also from what I've noticed they used this battery for the single channel ones in the two channel ones they don't have it anymore.

konsum wrote:

There is a lot of negativity about the fast dead battery...

The fast "dead" battery is first and foremost a great business. The global market for lozenge batteries was estimated to be around $4.9-5.6 billion in 2024. But scenarios assume strong and steady growth and a doubling of its value over the next decade. That is, in the years up to 2030-2035, this market is expected to reach a value of around USD 9-11 billion. This is the reality. Therefore, in order for those who are to get to earn as much as they want, the batteries in this type of device have to wear out. Of course, from the point of view of these market players, the faster they die, the better

Looking even more broadly, the modern purchaser only ostensibly becomes the owner of such a device. In fact, he or she is actually something of a 'renter', because, after all, he or she depends entirely on the operator for the control application and the periodic replacement of software and batteries. It is enough for the manufacturer to stop updating and supporting the software, and these hundreds of still-functional gadgets will turn into useless scrap. The same will happen if the batteries are not replaced.