First, I commend the user interface design, simple and very understandable User interface plus I love the dark mode option(I've always loved dark mode!). Cool user experience too with the animations.

But, first, the transaction fee is very high and easily turns away users, especially when you're changing steem to usdt. Custodian exchanges charge way less, I'm sure most people will prefer a cheaper option.

Secondly, the arrangement of the exchange options on mobile is a bit poor, the way the exchange options are stacked (the usdt, trx e.t.c) is a good user interface but a poor user experience, a simple horizontal display will be better and will accommodate other options to be added (except if the team is not thinking about adding more exchange options)

Again, the site is a bit too 'steem centred', in my opinion, there should be a a simple widget that displays the current exchange rate of all coins listed on the platform, this will help users make decisions easier.

Again, the team might want to create a smart contract token which will be used to reward users for exchanging on the platform,Amount of token rewarded to a user will be determined by the volume they exchanged and will be sent automatically to their accounts after the exchange.
This token will also be available to be exchanged on the platform, this will surely draw more interest to the platform, however, this just an opinion.

Nice work in summary, there's every room for improvements.