No, that's a really good point about running a computer just to keep wallets open for staking. My electricity costs $0.12/kw-hr so running that laptop costs me around $0.10 per day and I can guarantee you it isn't earning anywhere close to that from staking two different POS coins. Fortunately, I use the laptop to monitor my mining rigs as well so it would be running 24/7, anyway.
Yeah I think you got my point whereas others didnt!
A modern hardware laptop would be good, but there's bound to be people using old rigs with poor hardware efficiency leaving them on 24/7. I use a power meter at the wall so know from a variety of systems that all the watts add up and counts when mining/staking/zombie use etc.