Xfinity Stream - why locals channels and or programming require WIFI

I have used Youtube TV and Hulu LIve in the past...  never had issues traveling and streaming local channels. 

I switched to Xfinity TV using Xfinity Stream recently and noticed I constantly have issues with streaming the local channels... NFL game required wifi signal for example.  I was traveling and noticed the local channel wasn't availble... but it worked fine in same area for YouTube TV And Hulu Live?

when will xfinity stream act very simliar to YouTube TV And Hulu Live in regards to streaming local channels... those products offer the local channel in the area for CBS, NBC, Fox, and ABC.  Hoping soon xfinity stream can catch up on rights and agreements?

any ideas on when?