I think that hobbyists of Maya need MEL for some specific things only (ex: I don't know how you would do anything with particles without MEL, but that's just me). I find MEL especially difficult to generate and manipulate geometry. I tried to make a script that worked with polygons at CV level, for example, and that got me swearing in 3 different languages... and I am no beginner programmer either!
I can see how in a company it would be used extensively to automatize parts of the workflow or operations done so frequently that you'd rather launch a script than repeat them over and over. But people toying with Maya at home probably find it easier to do things by hand than writing a script. At least that's the case for me...

PS: I found this great site because Mark Wilkins mentioned it in the Alias newsgroup, by the way. Thank you Mark!