Aha, yes of course I'm only talking about cases where the actual processing time is over 1 second and you can't help but make the user wait (or do something else in app in the meanwhile)...
Delaying a 1 sec process to show me 10 sec of ads is one of the many definitions of evil
Sometimes the ads are subtle. Tax software isn't showing ads directly - they are just trying to give the idea that taxes are hard and so you should be glad to pay a lot of money for it - even though all the calculations are a few ms for any modern computer once it has the data. However if you think taxes are easy the whole industry goes away.
Delaying a 1 sec process to show me 10 sec of ads is one of the many definitions of evil