its very seldom used on the streets. for the most part, there arent to many situations on the streets u'll find urself needing to rev-match unless ur out on a winding road for some spirited driving... it does put a little stress on ur tranny, but if done correctly, wont be extremely bad. for sure not as bad as just droping a gear, letting the revs jump, have everything lurch and ur clutch get burned up. the point is to use both brakes and engine to slow u down smooth and fast. it'll also leave urself in the right gear and rpm for afast corner exit speed. it is extremely usefull in demanding conditions such as racing where u may need to go from high speeds to very low speeds quickly before entering a turn. once u've shifted into the lower gear, u'll already be setup to exit the turn just before u enter it. enter slow, exit fast.

best bet on the streets, leave ur car in w/e gear ur already in and apply the brakes. u'll be using both the brakes and engine to slow downwithout straining the clutch by downshifting. once the revs have gone down to about 1500, put it in neutral and just use the brakes the rest of the way to stop.

remember, brake pads are much cheaper and easier to replace than a clutch..