Just a shame that this bank note is basically unusable
Having said that, when I have friends visit from Singapore, they often seem to carry £50 notes... and most places seem to accept them (although maybe this is less true outside London).
[1] https://www.bankofengland.co.uk/knowledgebank/what-is-legal-...
It's more likely a concern about a counterfeit note, although I've never had that problem with a €50.
And a policy of "no €50s" is simpler and clearer than a policy of "€50s accepted only if we have at least 2 €20s in the till" which means customers won't know if they can pay until they reach the till.
The reasons a small business might not keep a large float of €20s in their till is probably obvious!
That problems happen if you try to use the 100EUR one and obove.