Unfortunately this service only generates BTC native addresses. You should consider switching to BTC native segwit addresses to support all bitcoin shipments at a lower cost.
I also suggest a feature so that users can download the phrase seed into the txt extension when creating a new wallet, manually copying the seed phrase is not efficient. Also the private key export feature of each address such as blockchain.com might be better. Saving only 1 seed phrase for several addresses I think is very risky.
I still prefer to own my Pvkeys and not let others do it for me, a lot of wallets do this But Personally I prefer to keep it on my full control.
I think you should improving by using some more altcoins into the wallet, for now I don't see any benefit to use it, a lot of wallets already uses the same coins that you have now.
Thank you for the comments. These are all valid and helpful points and these are features we have been working on adding as we gain market traction. Where we see the unique benefit of Cointeller is the ability to create a Bitcoin, Litecoin and Ethereum wallet in a matter of seconds, with no download, registration or identifying information required. The majority of our users have been using the Cointeller platform for single transactions and then discarding the wallet. That is the main feature of this system. We will nevertheless be adding Segwit as you mentioned for Bitcoin transactions and private key export per coin. Thank you for taking the time to review the platform.