A properly set-up horn should not, IMO, require a high degree of skill to play it, whether it's 'student' or 'pro'.
(Although I was surprised at finding it virtually impossible, as a beginner, to get any sort of musical sound from 3 new Borganis, while I found a Yani S901....and a Ref 54....and, of course, my Hanson 'Intermediate'!...really easy and pleasant

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The answer might simply be that professional sax players *usually* play 'pro' horns (as do many reasonably well-heeled non-pros!)...... find out what all your favourite pros play, and you have a clue !
Penniless students often, but not always, play 'student' horns !