Nothing of what he says is extreme... that's how you do it if you care for the battery, want a long service life out of them & want to prevent disastrous events airborne .
Some claim that they can afford buying new batteries & doesn't care about service life... they prefer to have immediate access to fully charged batteries all the time. All that is good... except the fact that you never knows when a battery takes it's "last breath" and give up, either due to a failing cell or a rapid swelling that pushes the battery out of the drone. Imagine if flying over some inaccessible lands or water & one cell in the battery fails & falls below 3.0V... a DJI drone will here start a forced auto landing which you can't stop. Or the battery swells rapidly & gets pushed out of the drone cutting the power completely, the drone will fall like a rock... neither of these 2 incidents will usually end well & in most cases the incidents originate out from how the batteries have been treated.