Hi @Lazare, I am the dude who posted that reddit post.

The $25 game cost me 0.00424232 BTC (around $32.96 USD at that time). I transferred that much to them, but the network fees for some reason raised within that 2.5 hours. 3 cents. And they cancelled it. The fees were 0.00038932 BTC

It is messed up. Sending money from Coinbase to BitPay, for $29 resulted in $32 dollar in fees.

Nevertheless, this experiment showing a bunch of friends (~10) why Bitcoin is the worst payment provider. Network fees are not calculated correctly, transaction fees too. And at the end, this 3 cents difference from the transaction fees made a big deal.

And worse of all, customer support doesn't exist for the consumer at all when they pay for Bitcoin.