The upgrade to the faster plan is cheap however for your average user is pretty much pointless. It's like having a Ferrari and driving down the interstate, the car can go 200mph but the road won't allow it. The cheap plan has speeds above and beyond what your average server is going to provide. The fastest download of a large file from this site I've seen was about 1000KB/s which is roughly 10000kbps. Unless you're downloading massive amounts of files and data from very fast servers the faster speed is really irrelevant. A typical site on the internet is not going to have the speeds this site has. Most that I have come across you''ll be able to get file in the 300 to 600KB/s speed.
Your browser which actually take more time to render the page than it takes to receive the data. It takes about .1 to .2 seconds for the script to execute on the server (this BTW will be getting faster shortly
). You'll have another tenth or two of millisecond to download the page itself and that can increse depending on the amount of images but its not that much. Then maybe a half a second to render the page. Overall any page on average should be viewable in about a second. For a site like this a faster download time becomes useless because you have bottle necks elsewhere specifically the time it takes the browser to render the page.
Lastly video is the one thing that requires a lot of bandwidth, however the streams being provided by servers are pretty low compared to your overall speed. A typical "HD" stream from a server is going to be about 2000-3000kbps which is well below the max speed of a the cheap plan. Speeds like that for video are rare and usually on pay to view sites. On free sites like youtube they are in the 250kbps to 500kbps second range. Your average youtube video is 250kbps. If you're on a faster DSL connection and getting glitches in the speed of the video chances are its on youtube's end not yours.