What's the difference, at least in practice, between binning and downsampling?
Both lineskipping and binning are objectively incorrect designs because they change the sampling from what the antialiasing filter was designed for.
The purpose of the antialiasing filter is to spread light across adjacent pixels so that the camera does not see things that are not there. It has to be designed for that particular pixel pitch (so that it blurs into the next pixel, and not the next 2). When you introduce line skipping with video the antialiasing filter that was there for stills doesn't work. Binning is no better regarding aliasing, because it's still sampling at the same lower spatial frequency as lineskipping; its only advantage over lineskipping is lower noise.
With downsampling, the camera is taking the antialiased data and then interpolating between those values to find the correct value.
If a camera uses lineskipping, one of two things is true: (i) the engineers did not understand sampling theory, or (ii) the maker did not want to spend the money to put a decent processor in the camera. Either way, I wouldn't buy such a camera. If Sony could put true downsampling in the original RX10, it should be in a 2019 Canon 7D successor.