The company is warning that consoles that go for longer than six months without charging might somehow get spoilt and that when gamers try to charge it again, it won’t work. If you are actively playing your Switch, there’s a good chance it’s left in the dock which means that it should always be charging, so this isn’t an issue.
However, we imagine that there might be some gamers who are concerned about the battery life of the Switch and are worried that the console being constantly charged could degrade the battery life. This is a legitimate concern as the problem with lithium ion batteries is that over time and with constant charging and discharging, it starts to lose its maximum capacity.
https://twitter.com/nintendo_cs/status/1310415215570251777
This means that like our smartphones, eventually a 100% charged Switch when taken out of the dock might not last as long as it did when it was brand new. Nintendo has acknowledged this, but they also note that it is safe to do so. We should also point out that the Switch’s battery can be replaced worst comes to worst, so you don’t have to worry about the console being rendered completely useless.