It's not a good idea to other coins address from an ethereum address or a bitcoin address or anything like that!

Because they don't explain the process of how they go about and generate that address, so if that service does down or becomes inaccessible, you will permanently lose access to your funds in that generated address despite having the private key to your Ethereum address, because you literally do not know how they are making the Bitcoin address.

A much better way is to use the seed phrase and derive a bitcoin address using its derivation paths like m/'44/0'/0', m/84'/0'/0' and so on.