Maybe in your country, that's why it is so hard to make an estimation
For example:
https://coinatmradar.com/city/296/bitcoin-atm-valencia/Buy: 5.3%
Sell: 2.6%
7.5% might sound lower than probably half of the BATMs in the US but it's highly likely is higher than almost all around here

Not sure where you get those numbers. I went on the link and most BUY rates are at 8.5% or Fees N/A or "unknown" (Bitbase at 10.5%!

) ... a couple in Madrid at 5-6% but no way an average of 5.3%?
Anyway, I understand the lower the better. It's a matter of finding a price equilibrium to stay both competitive and profitable. On the other hand, no need to compete with exchanges, only other BATMs.