and all the extra time transcoding as well as storage for the transcoded files.. and you are making an assumption about the video working 'better' and having a smaller filesize given you don't know the properties of whatever file he's inputting or output settings he'll choose.
Converting for the tablet is necessary in some cases, and a waste of time and space in others.
it takes some time, but you can just run it and come back later. storage on a desktop computer is negligable, especially when the output files are so small. it's a fair assumption. video that looks halfway decent on a desktop isn't going to work well, if at all on the tablet. after i convert, the file size is about half.