It has no advantages because it is close source and because there are many open source noncustodial wallets that are supporting USDT already.
That's the advantage, actually, but not the source because, like you said, it's closed source.
I tried the app and explored, and they only support 3 assets that support multiple networks: Bitcoin, USDT, and XAUT/Gold (this is what I mean by advantage compared to Electrum, which only supports Bitcoin).
The wallet is similar to some exchange wallets; I think it is likely a Bitget wallet or Coinbase wallet, where you have two options to back up your wallet via a 12-seed phrase or via cloud backup, which is not safe.
But since the wallet is source code, it is not safe to use, and then users can't audit the wallet; we do not know if the wallet has a backdoor or something hidden running on the app.
Anyway, if they change this in the future to open-source, why not? It is a good alternative wallet where we can store gold, USDT, and BTC.