Submitting changes is not unnecessary. It’s even listed in the tips section of the EVE Uni Wiki:
Planetary Interaction - EVE University Wiki
“Until you click the “submit” button, no actual changes are made to your colony. This allows you to experiment with different setups without committing to them.”
You can fiddle around with setups and times before spending ISK or committing to the timeframes.
That’s a little too plug and play. If it was that easy to make passive ISK then what’s the point?
You can double click on any structure to go to it’s default page i.e. extractors go to the extraction program.
What happens when you log back in and find a customs office changed to 50% tax and drained your bank account exporting P4s over the week? Also it might be possible to accidentally make a loop of automatic import/exports with the wrong setup. That would make people very unhappy.
PI is supposed to take work just like any other activity in EVE. Right now I have 4 planets set up and it takes me less than 5 minutes to reset extractors, and less than 15 to transport materials when necessary. As is it’s almost like making free ISK once set up.