Interpolation.
Interlaced footage is only half resolution as progressive footage. I honestly see zero reason why they still make cameras that shoot interlaced (unless it records to tape).
shooting 25p will look MUCH better, but you have to be more on top of your shit. Your pans have to match the movement of your subject almost perfectly if you don't want any strobing. It's hard, but it looks really good, so have at it!