I think it is because it is also harmful to be at 100%, not only to charge there. So a docked deck will be longer in a harmful state than a mobile one. In the case of a mobile deck there is a clear use case for charging to 100%: Longer battery life.

But you are also correct: If you’re not using the full battery charge during everyday operations, you should also enable that and also buy one of those 4-5m USB-C charging cables

If your deck is docked, it will always be at 100% charge

Because you can now just set the charging level to 80%, plugin your Deck into your dock and it will stop charging at 80% and then just use passthrough power.

How would something like that even work? Create a driver that phones home is somehow able to figure out the location of the computer by some method that is not easily defeated with a VPN? Even a GPS chip on the cards won’t work in a datacenter rack

Batteries really do not like to be at 100% charge. So if you use your SteamDeck mostly docked, it will be always at 100% charge and this prevents this. It’s a nice, useful feature.

And those lifetime subscriptions are also a trap. They know that you have the money and are willing to pay and that you’re using their service. Do you really think that some business suit will be satisfied by your onetime payment back in 2022?