JeromeTash, the account secret key is not the same as private keys. If clients see the seed phrase, they may try to use it in another wallet and that may cause some confusion. However, when they see the secret key, they will remember that it is for a Nummix account.
I understand, but it would still give them lots of options to recover their funds just in case your website goes offline for example.
Without an option to back up the seeds or even just a private key for each address, you are giving your users no chance to trust your website to always be online for them to access their accounts using a secret key that can only work on your website.