Having done both art painting with acrylic and building painting with acrylic-based paints, I don't know that I completely agree that art acrylics are better for wall coating than wall paints. No small part of the higher price for art acrylics vs wall paint acrylics is the pigment density. A blue that looks back into you when you look at it can be entirely appropriate for artistic work. Or, if it's not supposed to be the blue that's looking into your soul, you can mix that cobalt blue with a mars yellow to get the exactly correct shade green needed, because you're never going to get the green you want using a phthalo green as your base. Most people neither want nor need the intensity of color, nor the color flexibility that comes with art paints when it comes to their wall colors.

Additionally, art acrylics are typically very thick, to allow the artist a high degree of flexibility in application density, a flexibility that's just not needed for wall application. You correctly note that labor is the major cost for house repair. In light of that, it strikes me as silly to buy a bunch of extra-thick art paint and take the time to thinning it down the the appropriate consistency for wall application, instead of just buying a volume of paint that was already at the appropriate viscosity.

An acrylic-latex intended for outdoor use is going to be formulated to account for the fact that exterior surfaces see wider temperature swings in the summer and winter, and will be more flexible in its final cured form, reducing the flaking and cracking caused by the temperature-driven expansion and contraction that comes with the seasons. The formulation is also likely to account for the greater UV exposure its going to have outside. If you try to coat the exterior of your house with art paints, you're going to be spending a lot more money, it it might not last as long than if you used a paint intended for the purpose.

Now, if your goal in either scenario is art or aesthetics, than that's a completely separate discussion. If you want the wall of your house that faces the local park to be a mural highlighting fundamental truths of the human condition, more power to you. Though, in that case, you might do better to eschew pre-forumlated paints entirely, and instead buy the raw outdoor-use formulated resins and pigments yourself, and mix as appropriate.

> The last time I let my university landlord paint my apartment, it took days to clear the furniture, and I was instructed to do no paint prep. There were peels coming down from the ceiling. The painters exploited this "paint is glue" theory by painting under the peels and pushing them flat. I channeled my desire to kill them on the spot by politely escorted them out in mid-job and never letting anyone paint for me again.

Okay, that's just sloppy work. I'd have wanted to kill them too. When I was painting commercially, if I or my supervisors had caught anyone doing that, said slacker would be off the crew permanently.