stupid strategic question

[John Beaman]

I have been reading the new book, Dragons On Bird Wings (well-done BTW) so, I’m going to ask a stupid question about USSR strategy in 1943. In the spring, after the elimination of the Stalingrad pocket and other places, the Red Army was sweeping westward, albeit with hiccups here and there. They had isolated German forces in the Kuban peninsula and according to this book spent an enormous amount of army and air force resources trying to push these German forces out or eliminate them. Losses seem to have been very high.

My stupid question is: since Soviet forces were driving west north of the Sea of Asov and would cut off German forces, anyway, why spend all that effort to eliminate a small (relatively) bridgehead that the Germans were very unlikely to use as a springboard to a renewed attack into the Caucasus? Why not just let these German forces wither on the vine and keep them from retreating to the Crimea by airpower? Surely, Soviet forces employed here could have been better used elsewhere?

Thanks