That is what I thought.... :D
Firstly, it saves your power button from wear. Sometimes you might have dirty fingers or your phone is flat on a desk and you have only 1 hand free. For both of these, an on-screen button is great. On my One Plus, I never use the physical button now.
Oh dear, thanks so much for this, actually never noticed it's already present in Huawei, cheers Masteryates!
Xiaomi phones have this to... It's a widget if you have their os.. Miui os not Google one
What's wrong with just pressing the power button? (confused)