The amount of time FGO actually stays open per day for a specific reason on dead weeks is abysmally low compared to E7.
I agree the app stays open longer... but having to hit confirm, try again, start every 5 minutes isn't exactly time consuming for me... and if I'm doing other things like typing this post right here, watching youtube, playing another game, planning what I need to farm to get ready for seraph etc the actual time investment in E7 is very low.