The downside to the compress (other than the one you mentioned) is the simple fact that I can't always just nuke my little eye-pad thing and lean back for 10 minutes several times per day at work. Even when I'm able to do it a few times per day as my eye doctors have suggested, any relief is relatively short-lived and doesn't treat anything long-term.
It sucks because my eyes almost always feel irritated or dry and no manner of lubricating drops, antibiotic drops, or hot compresses have helped. I've tried a few less tested but ultimately harmless things like fish oil supplements (since they're cheap and effects seem to range from unnoticeable to possible systemic benefits in the long term).
My takeaway has been that there's really no "cure" for blepharitis or chronic inflammation and meibomian gland dysfunction. All you can really do is minimize the things that exacerbate it and deal with it.