encryption – Encrypting a password with its own hash

I just found out that an e-commerce platform (similar to Shopify) I was planning on using allows me to see my password. I know I can’t assume anything and I should (probably) just run away from it, but it got me curious: is there a way to do it securely?

I mean, what if they use the password’s hash as an encryption key to encrypt the password itself? If done properly, could something like this be a reasonable solution?

Moreover, does anyone have any idea why on earth an e-commerce platform would choose to do it?

And no, I don’t plan to implement anything like this.