Yes, because both Masha and Vee bonded like friends and all and Vee would like to show her the Boiling Isles and the demon realm and show Masha her real self to open up truthfully to her more. You know, Vee does that for Masha so they can be closer together.
The others I just don't think they'd be able to handle it or they just didn't really bond with Luz or anyone she loves which I was thinking that if a human should go to the Boiling Isles. It should be Masha because she bonded Vee and Vee would probably like to show Masha the world she's from, everything about it and show Masha who she really is. I just think it makes more sense that way.