I have had unboosting built into my bot all year. A recent development is a container next to labs to catch the boosts so that I don't have to find a porter creep to get there ASAP after the unboost and pick up the boosts as they tick down. I expect to be typically unboosting 1 or 2 creeps per lifetime so the energy cost of the container is justified if it saves a few 10s of boosts per creep lifetime.
To me, unboosting is a way of getting hold of complicated boosts for "free"-ish. If you only produce into 8 labs then you have 2 labs you can unboost into at no cost. Even if those two labs are on cooldown (which sometimes happens for my bot), paying the lab cooldown cost of building the boosts without having to pay for the minerals seems like a good swap to me.
There may be people with perfect mineral set-up, but I find that there are some minerals that I obtain more than my empire can use, and there are some minerals that my empire is to an extent gated by. Particularly if the boost contains one of these gated minerals, unboosting seems like a massive win for me - it either leads to me producing more of the bottleneck boosts, or it leads to me obtaining more credits.
I haven't run into the issue with a level 7 room that you've experienced, but at RCL8 where you're only running 1 upgrader I have close to no issue with the cooldown time, even using T3 boosts for upgraders.