Have you never seen paid wifi hot-spot access?
>There are a million other reasons from privacy to p2p and beyond.
You still haven't given a real world example. It sounds like you're mad you can't seed on bittorrent effectively from your mobile.
>And lets not forget that all wireless telcos have absurdly low data caps
Sounds like you picked a bad plan. In the US all 4 national carriers offer unlimited (well technically softcap congestion depriority if you go >20-someGB) plans for under $100. I literally never switch my phone to wifi at home since LTE propagates better and I get more consistent speeds. (Carrier gave me a femtocell so I'm still using my cable ISP for backhaul there). I've scratched 20GB a few months and actively had to try to download livecd's in addition to my usual 320kbps spotify streaming to do it.
I have seen paid wifi hotspots. Luckily they don't absolutely destroy the wifi thoroughput like LTE-U does so I don't mind. Have you ever seen a free LTE service?
A real world example is my use of the Retroshare (application) for encrypted communcations. It uses the DHT network to bootstrap and requires accessible ports as do many other completely legit protocols. Not using centralized services to communicate takes lots of bandwidth and it takes real internet access, ports and all.
It sounds like you picked bad wifi equipment for your home network.
As for directional antenna, the antenna doesn't effect propagation, which is a function of wavelength, which is what we were discussing. Obviously having more of the signal directed in one direction mitigates the marginal propagation at higher frequencies. But a sector antenna isn't exactly omni and down-tilt to limit cell horizon is still going to include lots of people and buildings.
Your scarecrow argument about webserver on a phone as the only reason for having a real connection is either laughable or intentionally disengenuous. There are a million other reasons from privacy to p2p and beyond.
And lets not forget that all wireless telcos have absurdly low data caps; that's the primary reason most people switch to wifi instead of staying on their LTE connection.