ATM's in the Netherlands cap at 50€ (so any higher denomination must be requested at the bank), due to people using contactless payments frequently there's less incentive for cash. Even then, why did the EU decide to print 100€ or 200€ notes (forget about a 500€ note as they've stopped printing more since 2019 but it is still legal tender). Stores refuse to accept a 200€ note for a 150€ purchase, why do these denominations exist?
Well first of all it's just easier storage for mid-high amounts of cash. It'll take almost double the volume to keep the same amount in 50's and takes twice as long to count so if someone does pay for something expensive in cash, 100's are a lot more practical.
The other aspect I wouldn't neglect is inflation. Today's 50s will be 100s in a few decades so those bills will become a lot more relevant.