It would only be interesting if you can output the video in full resolution to TV-out on your HD TV, THEN and ONLY THEN it will be interesting..
I can Reencode your 720p videos to 480 on my pc and watch them with maemo @500MHz, isnt this better for your limited Space on your Phone? I would rather copy 900MB videos instead of ~4,5GB ... You dont see any difference if the reencoding is good...