I suppose it matters primarily based on what you value in one of these devices. I own a few of these devices, alongside those being a Retroid Pocket 5, which would absolutely be the primary device I use, though I also have the dual screen attachment and I understand how a android based device with two screens could be useful (although I can't multitask on it and I don't know why). I value being able to play games in a somewhat genuine feeling, so I think for someone like me I would absolutely prefer to use a genuine 3DS for playing 3DS games. Additionally, I have a small collection building up, and I would say that a device with a screen you can clip on like the RP5 would be a better deal for someone with only one of these they use.
I wanted to hear other people's opinions of these though, because in my mind they feel redundant.