Frosted Lens or Deeper Channel to Hide Dots?
Depth does more of the work. Setting the emitters further back from the diffusing surface gives neighboring beams room to overlap before they arrive, and that overlap is what smooths the pattern. A frosted lens scatters light as it passes through, which helps, but it is working on light that has already arrived separated. Put the frosted lens or deeper channel question another way: depth is the stronger tool wherever the detail can give up the depth, and the lens is what you reach for when it cannot.
Neither one erases dots. A channel and diffuser together reduce the visible pattern without guaranteeing its removal, because what you finally see also depends on the density and format of the strip, the depth of the channel, and which diffuser sits in it.
Distance is what mixes the beams
Depth works early in the path. Every emitter throws a cone of light. The further that cone travels before it meets the diffuser, the wider it has spread and the more of its neighbor it overlaps. Give it enough distance and the beams have already mixed by the time they reach the lens, which is why a deeper channel behind the same lens can read noticeably smoother.
There is a second benefit that has nothing to do with appearance. A strip generates heat in use, and an aluminum channel helps dissipate it as well as giving the tape a flat, clean surface to sit on. That is a reason to use a channel in its own right, though a channel is not mandatory on every install.
