I would not be surprised if one day I see you complain that your funds are stolen because you downloaded some file from some website. How convenient it must be for hackers that someone would actually use their work and hand their private keys.
Correct, of course right now we can say that this is a good tool to used.
However, one day we might see someone bitching around the community and say that he had lost his
BTC when using some online tools that supposedly clean. Could be good if you are not playing with huge amount of BTC here, just to get how the supposedly conversion works.
But better to stay with
BTC and then separate your funds with Ethereum, just saying.
I agree with that I think this kind of method is completely unnecessary, Also this is not how the system works. Your method might work but I don't think anybody is going to risk their funds in this method.
Anyway, it is more secure if you are justs going to follow and create a different wallet address for BTC and Ethereum since this is how it works, and for sure it will be fixed soon so completely not recommended for everybody.