Yes, absolutely. Not only is it useful for reflecting on your own performance, but when it comes time to analyze the performance of
others this is invaluable as well.
The most important thing to make this footage useful, in my opinion, is to develop an effective system of recording matches, such that retrieving the correct information is trivial.
For the past two years for us, this has consisted of recording raw DV footage straight to a laptop via Firewire (using an application called "WinDV" on Windows XP), and
labeling them as matches end (it saved us from
many instances of "well, the match was
supposed to have started around this time..."). The raw DV footage for an entire 60 or so matches at a regional typically consumes around 100GB for interlaced footage (the only mode that was available on our old camera), and 15-20MB per match when encoded as described
in this thread. Further reductions were had by cropping the footage during the step right before encoding (which, conveniently, also allowed me to view the "official" footage right alongside mine perfectly on my laptop display).