The answer to the second question: most online resources are compressed in a way of large image loss and small volume, which is "clear" only because there is no comparison result.
Back to the first question, first of all, these vendors will adopt public or free solutions to give users better compatibility, such as H264 series, Mpeg4-4, avi and so on. They can let users use it at will without extra charge. These schemes are all compressed without affecting the image quality as much as possible (avi is not 100% uncompressed, but the processing methods are different). However, those rmvb are small in size but lose a lot of image quality, so they cannot be used as a pre-recording processing scheme. Better pictures help to present better picture effects in later editing. And rmvb is a patent of realone. Suppose those camera equipment companies use this technology, they need to pay realone a lot of patent fees.
It's a little confusing, but the meaning is similar.
In short, it makes sense and is not chaotic.