Most stuff is digital these days. Speed is measured by counting number of impulses (wheel rotations) per unit of time, then displayed analogly on dash board using servos and similar. There are many reasons behind this. Some of them are legacy and people are simply use to them. Other is that analog you don’t really have to look at them to read them. Just a mere positioning is enough to tell you approximate values. There are aesthetics involved as well. Readability in strong light. Etc.