Binance is good. But not all of their partners are.
Here's my experience with Koinal_io.
TL;DR - Koinal_io scammed me 2% worth of money of the trade. I recommend staying away from it.
I made a Bitcoin purchase on Koinal_io. The order clearly states the words "You Pay: XXXX USD" with all fee included. Koinal_io claims they charge in USD and all the exchange fee if any are charged by the bank (Spoiler: It is not true). Image of their helpdesk: https://imgur.com/a/EQRHUPv .
I selected a HKD Visa credit card issued by a big name multinational US bank. The card has no fee on currency exchange or quasi-cash transaction. I used the same card with another crypto currency purchase and have no issue at all.
At the moment I finished my purchase, I found that they charged me in HKD instead of USD. The amount is 2% higher than the Visa rate (i.e. there are a fiat currency exchange fee included). This forced me to pay the HKD to USD exchange fee charge by them.
Before the Bitcoin transaction went into the mempool, I immediately asked the support to cancel the transaction. But they ignored and refused. After receiving the Bitcoin, I submitted another ticket (ticket number 5505) requesting them to refund the 2%. I made multiple requests but they refused all. They lied about the transaction was charged in USD and the 2% was charged by my bank. They tried everything to get away from the responsibilities of their scam or their mistake.
My credit card is issued by a creditable bank. They confirmed me multiple times that Koinal_io charged me in HKD (2% higher) and the bank charged nothing. Koinal_io violates Visa rules on dynamic currency conversion and the bank recommended me to file a transaction dispute.
I filed the dispute and successfully get the 2% refunded. A big thank to my bank.
Avoid Koinal_io at all cost so that you are free from the difficulties I faced and Koinal_io's lies.