The problem comes in when people assume that mobile technology is a replacement option for a residential internet connection. For as great as 4g lte is, you do not want to try to play any kind of game you expect any amount of low latency on, even potato games like league of legends. MMO's are out of the question, and trying to stream anything would be patchy at best.
As an example, if you say, have a computer that you remote into for security reasons or what have you, that desktop is on a dedicated residential line, your phone is on 4g lte, and trying to scroll a page has so much latency it is disorienting. That is just performance, once you start to factor in costs of a $50 hotspot device, plus ~$16 a gigabyte and all of a sudden watching a public domain movie becomes a ~$20-$30 experience in data alone.
In my opinion, saying that mobile internet is really an option at all is just conditioning people to be used to metered connections that can be just as patchy as dial up used to be.