"They're crap. Why are they so crap?"
Because the power socket on a laptop tends to be very weak and very easily broken, I get about 1 every couple of months from friends and friends of friends to dismantle and replace the power socket where they have been broken. they are not an expensive part but it normally involves a total strip down of the laptop to get access to the part which can be very time consuming.
Modern laptop batteries do not need to be regularly discharged for purposes of maintaining the battery, they do need to be discharged regularly so the charging electronics has an idea of what is full and what is empty otherwise the laptop can get into the state where it will shut it's self off while there is charge left in a battery because it's lost track of what an empty battery looks like.