Yup! The T-54/55 is really simple in use tanks (first models designed in 1946-1947) and you shouldn't elevate barrel to reload gun. Well, I'm not pretty sure about latest models (designed in 1980s).
About loaders and autoloaders: you should remember that alive guy will get tired soon enough and couldn't support such fire rate as 3 sec for shot He must take an ammo (30-40 kg each round {I'm not sure about weight}) and put it in gun (and he must aware not lost his fingers "evil grin"). Still he need to remove empty shells (if any) and place it back on shelves/containers... I even don't say a word about British tanks with rifled-barrel guns and
compound ammos...
Any of system (loader or autoloader) has it's merits and demerits. But AFAIK the development of tanks (at least in Western countries) is directed at creation of tank with crew of two men (driver and TC). Drive drives, TC finds targets, AI hits them, autoloader reloads the gun
SFMBE