Actually, I disagree. With a competent team, you can run an Elite Space STF in about 10-20 minutes. For that, you get nearly 1k dilithium, a bunch of Omega Marks, the vendorable drops/rewards (which will usually net you anywhere from 50-200k EC) AND the Borg Neural Processors, which can also be used to net you another 1k dilithium for every 5 BNPs.
Compared to a number of areas in the game, the eSTFs are already chock-full of rewards.
EDIT: Plus, you can get certain valuable gear using the Omega marks and the BNPs.