Yes, MewConnect is the only official application that MEW had launched. Any application other than that are likely traps laid out to steal your information.
But I think MewConnect requires to be connected to MEW through desktop to work. (haven't tried yet but seems like it from the guide:
https://kb.myetherwallet.com/posts/mewconnect/mewconnect-user-guide/)
I dont know if MEW already has a mobile app but if nothing like that exist, then i think its about time the developers develop something like that for easy use. Guys what do you think
Is it necessary? IMO launching MEW from mobile browser is just fine and runs smoothly as well. Wonder why you are asking so?