That's the first I've heard of it!

In Casino de Marbella they have €10 minimum for blackjack. I have seen the €2.50 chips in the cash desk but never on the tables, the lowest denomination is €5 as that is the roulette minimum.

I was planning on getting a stack of varieties form the desk (ask the man politely) last time I was there but I lost my money in the cab and didn't realise unitl after I had entered the casino!