First off you break everything...and I mean everything so that is no longer valid.
Secondly, I too put the same cover on my Kowa. However I look at it as more of a theft protection device rather than protection from damage.

Not a big deal though as I put neoprene covers on my Zeiss and Swaro spotters as well.
I agree if you can swing and big and a small spotter than the Kowa is the best small spotter I have used by a WIDE margin.
If only going to have one spotter the Swaro 65mm is still the best alrounder IMO.
As for sheep hunting:
My buddy is looking through the Kowa 553 at the sheep he shot 30 mins after I took this photo. Granted we are less than a 1/2 mile from it at this point and this sheep was an easy no doubter but I judged it legal at over 2 miles away with the Kowa as well.
I actually put a larger Vortex defender cover on the objective and taped it on there and found it quite handy and quick and I won't lose it either.
Heck we even used it to spot impacts when I was shooting rocks at just under 2000 yards away in some serious mirage. And impacts at 1200 yards on 6" rocks was very easy to spot.