Yes, and Yes.
That hasn't stopped me from trying to put together a few more sets this way. I've got the Grand Carousel, Zombies, and Winter Toy Shop that I'm doing this way as well. They're a bit easier to put together than Mini Modulars, but it's definitely a pain in the ass.
I have around 75 lbs of bulk LEGO here that I'm in the process of sorting. So, it's been fun to separate, and then use the BL inventories to search for what I need. Once you factor in time spent looking for parts, though, it's definitely a money saver to just buy the original set.
All the above I want to keep, so I have a little more incentive to just BL it. But for stuff that I want just build and then get rid of (no room for it, no longer term desire to keep it, etc) I think it's worth it to just buy it and sell it later. For example, I'd love to build one of the retired modulars, so I will probably just buy it (even if it's in the $500 range), build it, and then sell it off. Even if I were to lose $40 on something like that, I would have gotten $40 worth of enjoyment out of it.