While anyone that has paid attention on this site knows what is best, real life time & budgets don't always allow it. As said in small amounts, no one will likely ever know unless you let the bare metal spot sit there uncoated long enough to start rusting without resanding or something else stupid that goes against common sense.
Whole paint jobs are done these days with self etch & 2k over metal. Accepted practice by many, just not as good.
I still have much of the same paint on a vehicle I painted back in 98' that had a few minor sand throughs in the epoxy & never showed up, just wouldn't let any go if I could easily avoid it. On an absolute high dollar paint job a sand through really calls for another spray & sand session on the panel for the absolute straightest reflective finish anyways. Also most sand through spots end up occurring out on the main panel faces, not on the more critical areas where you want the absolute best rust protection the most
Cutting any corners is always a personal call, but when you have higher than normal standards you can get away with some.