It's like a smart thermostat, always plugged in.

(Not exactly the same power feed but you know what I mean)

That can be an issue with a device that is always plugged in. Or with a device that is always unplugged, resting in a drawer somewhere. Or with a device that gets used with normal charge and discharge cycles. Or with things that are carefully-managed. tl;dr, it can be an issue.

I'm still waiting for the 9.7" iPad Pro that I have to swell up. I got it used, but AFAICT the battery is 10 years old at this point. It has definitely been plugged in ~24/7 since I got it.

Sometimes, I notice that has decided it's time to discharge itself somewhat and then recharge again. I assume this is for BMS calibration or battery health or both; I just let it do its thing and it's been fine.

Meanwhile: A disused Samsung Galaxy S7's battery swelled up enough to split the case open while I had it sitting on a shelf, switched off. It was about 6 years old at that point, and I was careful to leave it at about a 60% SoC when I put it on that shelf.

I haven't had the battery well up in phone that sees daily use -- yet. I won't be surprised if/when it happens.

That's old information, modern devices have better battery management

* Wired power required.