I have an iPhone 6s, jailbroken running iOS 10.3.3. In /Applications/, there are two apps, one named AdSheet and the other names iAdOptOut. What would happen if I deleted these with terminal? Would I no longer get adds?
If you deleted those apps, you would only not be able to get ads provided by Apple's AdSheet API. Apple doesn't support this API anymore, so it would only affect a very limited number of old(er) apps.