Yup. I'll qualify it: Very low temps can lead you toward jerky. Even though the temps are low, evaporaton occurs albeit more slowly than at higher temps. Still, rendering is slowed as well. The balance is the key. There is going to be evaporation, there is going to be rendering, the issue is not losing too much in the way of moisture by the time rendering has occurred sufficiently enough to cause tenderness.
Commercial back ribs are relatively lean. The operative issue, moreso though, is that they are relatively thin and relative to their thinness they have a lot of surface area. As the temps in the ribs rise, muscle fibers contract and squeeze out moisture. This ends up on the surfaces and some evaporates, some becomes drippings. At the point where the muscle fibers have squeezed about as much moisture out of the ribs as is likely to occur, the meat will, if tasted, read as dry--because it is--though it is undercooked. Rendering starts soon thereafter as temps rise further and it is the rendering and gelatinizing of connective tissue and soft fat deposits that creates what we know as 'moist'. (The rendering process also captures some remaining water, holding it in the meat.)
At very low temps, there is a good chance that the balance skews awry and the ribs lose too much moisture in the lag between it being squeezed out by the contraction of the fibers and the time when rendering begins, or the more exterior renderings have too much time to drip away before the more interior rendering is completed, or both.
Though I am not a fan of the approach nor the finish of the BRITU recipe, probably the main reason it works well is because the heat is bumped after initial slower cooking. This negates (or at least lessens dramatically) the chance of too slow a process taking place. It is possible cook backs at ~225 start to finish, but the line where it becomes more risky, imo, starts getting drawn at that temp and below.
Neither backs nor spares require low temps if one is cooking commercial pork. One can easily cook higher start-to-finish with superb results. The differences, as one would expect, is that the cooks are shorter, the 'done' window is narrower, and residual cooking can be more substantial (it doesn't need to be though; it depends on how you handle the ribs once done). It is a myth that higher cooktemps or temp spikes during cooking will cause dry ribs. Certainly temps higher than moderate are too high (for a number of reasons) but ribs can be successfully cooked at temps higher than what we think of as low/slow. Attention needs to be paid to the 'done' of course, but it is merely a matter of probing for tenderness, just like what is necessary for low/slows. Because they are leaner and thinner I cook backs at ~325, the fattier, thicker spares at ~275. I foil, often for flavor, but not always. It isn't required.