The restarting is independent from the games performance. Battle times actually eat into the time you have after the battle to update your team, and at some point restarting the game is faster than watching the battle unfold.
You can display ads, just not personalized ones. Might even lead to more static image or text based ads, which have a higher chance of not being blocked by users
Well, it's 2018, and most publishers rely on some 3rd party ad-tech to serve the ads. They don't have direct contracts with advertisers, and definitely has no tech in house. If 3rd party calls are prohibited, their ad revenue disappears overnight.
