it depends on the matchup and the map sometimes the shotgun is necessary for pacing and shouldnt hinder your ability to practice rockets considering the fight should be over after the first 4 rockets - depending on how you play
the reloaded ones dont count as practice and typically are these stupid desperation equaliser type shit anyway. lots of people do that shit and i cant see the point - it would be much better to have some sort of hitscan aim rather that jumping around with escape plan like a monkey
i think people had better aim before the gunboats thing and for a map like ammomod or maybe even badlands mid (to a lesser extent tho) it just encourages boring play, or vs scouts it makes the scout play just around viaduct rock only or some shit considering most scouts will just wanna cheese you, but gunboats are probably good for gully mid gran mid and spire cause its all leapfroggy and u can win with one rocket
this shit doesnt really matter though the most important thing about practicing and havig a good game is just that you are both humans