The company owned by the dude who thinks dictatorship is good and who put DHH into the board of directors?

Free phone plan? Wat? Is it ad supported or something?

I hate that the modern Web is almost unusable unless you have strong 4G. We used to be able to load WAP pages in a minute or two. There are so many scenarios today where I have less than ideal connection (inside buildings, in tunnels, in the country side, in long train rides...). This is a great solution for that.

I like seeing these solutions in the modern day. If you're looking to get even more use out of the limitations of your phone plan, you can take a page from computing history. Back when our mobile internet was 64kps-128kps we had these same challenges. I was doing remote server screen sharing on Windows with 19.2kps with VNC and could still perform important fixes in emergency situations.

Analogous to your situation though, a very clever approach was to use what was called a "clipping browser" such as Blazer for PalmOS.

It would work with a server with higher bandwidth to receive your web requests, fetch the contents to the clipping server where it would downscale the graphics and remove rich media elements (videos, animation). The result was a surprisingly fast loading graphical web experience. Keep in mind in those days a 320x240 screen was the limit, so you could downscale graphics quite a bit without losing any quality perceived by the end user.

You could probably accomplish this same thing with a modern Squid proxy server with a custom configuration.