That's a pretty common opinion but I disagree because SD3 often comes up as cluttered and visually messy, the detailing has no regards for visual clarity the worst offender being when you can't even tell where the exits on a screen are.

There are also many other SFC games that have a similar level of detail and/or which are more technically impressive with their use of visual effects but they're not as famous as SD3, because SD3 had legendary "the sequel of a game we like that we never got" status like Rondo of Blood which artificially increased its popularity before anyone got to even play it and this sort of notoriety just doesn't go away.