+2 -- I always engine brake to be in the right gear, and it's saved me more than once from stupid cage drivers in daily combat commuting.
I also don't buy the excessive wear argument.
The OP's issue was obviously massive heat/massive wear, caused by either (i) massive slipping/abuse of the clutch for long periods (certainly not caused by the OP's technique), or (ii) some mechanical issue which didn't allow the clutch to fully engage.
This condition simply could not be caused by engine braking. Think about it -- the amount of friction heat generated by 3-4 downshift clutch engagements is trival; the clutch is slipped far longer (and gets much hotter, and therefore wears more) when taking off from a standing start. These clutches are perfectly capable of going well in excess of 100k miles with or without engine braking.
To counter the "brake pads are cheaper than a clutch job" crowd, my view is:
(1) engine braking clutch wear is a theoretical concern for which there not only is no proof, but no technical reason to believe it is significant -- and therefore clutch wear is no reason to not engine brake,** and
(2) bike repair and hospital bills as a result of being in the wrong gear at the wrong time costs a lot more than either brake pads or clutch jobs.
** FWIW, I believe the "no engine braking" mantra arises from racing, where there *is* good reason to only use brakes to slow a car -- but that does not mean the same rule should apply to street driving.