For older players I don't think there's any real benefit beyond tradition. If I made a new edition, I'd be very tempted to basically make what is level 3 now, level 1 (in pretty much all regards), and in the DMG offer an optional "level 0" experience, which was heartily disrecommended for new players and designed as an OSR/nostalgia-trip deal.
It took us about 10 sessions to get to level 3. Everyone is different!
We don't use XP and our sessions typical run 4-6 hours. I stopped using XP in 1e and I have never gone back.WOW! I'm curious. How long was each session? Do you award XPs or do you use Milestones?
It took us about 10 sessions to get to level 3. Everyone is different!

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.