From that, it's clear it could be researched and used safely, and then they'd literally have access to the most efficient power source the galaxy has ever known!

My answer: I think they should. 7 of 9 was able to prove, albeit at the last second, that the Omega particle could become stable. Also, the planet where the Omega particle was being researched in MASS QUANTITIES didn't result in nearly the amount of destruction in the accident that Federation believes can be caused by a single particle. No chain reaction, no "light years of space with subspace ruptures" - they only had to run on impulse drive for a short while to leave the planet.