The argumentation seems to be focused largely on either irrelevant facets of theoretical scenarios, or notions of efficiency or the lack thereof.
Personally, I have my masons all currently set to make blocks, on repeat.
This has nothing to do with the ease with which constructions are made from blocks, though I noticed that before and was pleased with it. Honestly, for all the effort and hauling it would take to atom-smash the spare rocks in my fortress, it is JUST as easy for me to have them converted into blocks and then stored in a blocks/bars stockpile where they can be stored in BINS.
That is enough for me to have every single rock converted into blocks. No more hunting rocks to have them dumped to have them atom-smashed. I just put blocks on R, and walk away and any time I need a wall or bridge or paved road or whatever, it gets done in one third of the time. If I need anything from the masons, I queue up the task ahead of the blocks, or cancel out one of the mason's block-making duties, and then let him get back to it once my task is completed.
And really, if I still want to atom-smash the damned things, I just smash them with the bins and cut my losses. That may not amount to any trumping kind of efficiency, but it gives me a lot more time to focus on any variety of other projects that are more important and more conducive to both fun and Fun.