To be staking, yes. Also, the longer you keep it open, the more network connections your "node" makes within the network (the more you have, the better the odds of a sooner stake, unless I'm mistaken.)
The 24/7 is one reason I try to migrate wallets to a raspberry Pi 3. It only draws 4 watts or so of power and it takes up so little space on my desk. The downside is that I have teach myself linux, including commands and trouble-shooting.
Thank you very much for the explanation, that is what i wanted to know.
I am getting into rasperry slowly now as well.
Another idea would be to rent a server on which the wallet is open. But the raspberry version should cost less in the end.