Yeah...I found that blueprints were of limited use building structures because although you could put down foundations marginally faster than zooping (16 tiles rather than 10) 4x4 isn't a very convenient size for this, and if you have a lot of blueprints all at once the way a large building does the game doesn't handle it well.

With manifolds of machines it's a problem, because say you have a manifold of assemblers. Well there's a left-handed and a right-handed version of the input belt manifold. If you include an output belt, does it go the same or the opposite way of the input belts? Then if you need higher tier belts than you built it for, you either have to upgrade them once placed or go to a blueprint designer, make the change, notice 25 hours later that you missed one and that half your factory has been running at half speed the entire time because one Mk 2 belt didn't get replaced in a blueprint...

Oh and exactly one manufacturer fits. I don't think it's usable at all with refineries or coal generators even though you use a lot of those machines.

I vastly prefer the SMART mod, and probably by the time I've finished this playthrough, done something else for a year or two and am ready for another run of Satisfactory it'll be ready for 1.0.