Personally, when I opened the link yesterday, I wondered if I was looking at a product for 4-year olds: Big round shapes, bright colors, ... and nothing that would give me a clue about what I am actually looking at.
I might simply not be in it, but who's the target audience here?
According to my recent test, the premium was 4.7 percent compared to spot rates, hence their pricing is not competitive and Bitrefill remains without a serious contestant. There you'd only pay the ~0.5% fee for going through an instant exchange in order to have your XMR arrive as BTC.
EDIT: Now, a day later, I did another test and got percentages from 1.8 - 2.0 % which is much more reasonable.
Hint: To quickly get the hidden fees of any purchase, execute units like this:
./units.sh '<xmr-cost-at-checkout> XMR' '<EUR|USD|...>'
or./units.sh '<xmr-cost-at-checkout> XMR / <value-in-fiat> <EUR|USD|...>' '%'
for the total percentage asked.