I feel like The Internet has this urban myth that says keeping a charged battery plugged in all the time will eventually cause it to explode and burn your house down, guaranteed.
I get that keeping a battery at 100% charge is not great for it in terms of longevity (ability to hold a charge). And it's obvious that heating the battery up by running the laptop at full tilt inside a backpack or something will turn it into a spicy pillow.
But I struggle to imagine the failure mode that reliably shows up when keeping the laptop powered on 24x7 that is never a problem for 8-16 hours of continuous use while plugged in (a very typical work day for my laptops).
I ended up repairing the Mac, replacing the battery, and installing Chrome OS on it. (chrome sucks though, someday I’ll get it back out and switch to real Linux)
I had a MacBook Pro where the laptop worked but the battery became swollen so much that it distorted the case. If I wasn't there to notice it, it would probably burst at some point and Lithium is very flammable.
It's probably rare and overblown, but it can happen.