As a Th10 I find much better loot in Masters, so I keep my TH inside to keep my cups up as I just log off casually after raids. I'd have to play longer sessions to maintain this cup range with my TH outside so its simply more convenient to tuck it in and log off while the next army cooks. I don't get attacked much even when my loot is towards the cap and most of those are just blown revenges from gemmers.
During boost week I was actually upgrading both infernos so had my TH outside and my looting was actually worse than usual as I fell down to about 2300 cups and was sucked up in the nexting vortex.
While there certainly are some defensive losses, its quite a bit less than what I gain by having casual access to M3 bases/league bonus (plus, cups can be monetized rather nicely in M3 as if you're willing to dump 20 trophies you can turn that into loot easily so defensive wins are like a line of credit for profitable kamikaze attacks where you're not trying to win).
However, I do generally put my TH outside overnight as a full 8 hours offline would make the odds high of their being a serious attack and getting sniped once a day isn't much of a damper on my farming range.

