6 confirmations for a 20EUR giftcard seems a bit excessive and unnecessary, and would be something that would drive me to your competitors.
No confirmations are required. I've been using the site for a few months now and I never had any delays and I just did another test:
I just bought a 10 GBP VCC. I got an email from Coingate saying that the payment is complete just after sending the payment and shortly after, I got my code from Coinsbee as well.
TXID (Unconfirmed at the time of writing): https://www.blockchain.com/btc/tx/9941b8df97a3708c30cdc9ab5e21ac70351d76507f86459a91b3e1a6e70d2d6b
I'll try it out. (https://blockchair.com/bitcoin/transaction/1c5576df3feb42329fcd88d6b175ad4436405cc412adf19b5cbfd7b3aebbd674)
Perhaps it's because I'm using RBF? still, 1 confirmation should suffice.
Update: received my first confirmation. My inbox is still empty and it now says 1/6. https://i.imgur.com/DgvAAbP.png
Looks like we got 5 more confirmations to go.