If STR is your only concern, then yes, it's over kill.
BUT, what about IOPS. Drives with higher STRs, will also typically have higher IOPs (be it single-user or multi-user orientated), so while you may max out the STR on say reading a single 200MB file, you will still have plenty of room for random IO stuff (when the disk is the bottleneck and not the interface), where you may have 1000's of 4K reads and writes spread across the disk. What I'm trying to get at, is that STR is not the only measure of performance (and many would argue that it serves as a poor benchmark metric), and that IOPs for your given task should be the consideration as well.
PS. I live in a world where STR means nothing, but random IO is king.