Added to this, their fee estimation is pretty vague so you can't estimate the actual fee without looking into
https://mempool.space/ like site.
You can't see all the addresses until the created one atleast get a successful transaction.
So as said its good wallet for multiple coins but definitely not the one for Bitcoin.
I have not used it before for bitcoin. The last time I used Electrum wallet because the wallet do not have RBF. I could have used the wallet bit the RBF it does not have for bitcoin will not let me use it. Even if I am using Electrum, I still use jochen-hoenicke.de or mempool.space for fee. There can be a good wallet that do not estimate the fee accurately too.
If you send to the wallet, the address will change to another one bit you can not see all the addresses, that is true.
It is a good wallet for many coins but not also supporting many coins like that. There are many coins that it is not supporting and it is support just only the peg of other coins like doge. If you want me to begin, I can name many coins it is not supporting.