Well...if you do a lot of uploading it will improve. Most people don't upload much so it's more of a moot point (although browsers upload to send actions to the server, etc. but they use a tiny amount of data in doing so).
I guess you could seed torrents to take advantage of the upload speed. Or host a website lmao.
i tried using it as a hotspot and downloading some big files, but there is a cap on the wireless performance of the ipad. i get about 10 Mbps less in both download and upload via hotspot compared to using the LTE directly on the ipad.