From what I know...
to add to Knightwhosays_NI...
Looks do play a part in the sense that you must look presentable.(It's not a modelling show) How you present yourself is important, how confident you are and such. As I said, it's not an oral exam, it's a conversation that you have to keep with the interviewers or panel. If you go there shabbily, not neatly shaven, higlighted or long hair, looking like a cool dude, all these will definitely not pass you through.
It's not only about upgrading academically. You can take a PPL, or even advance to do a CPL/IR, etc... It can also be in terms of your job(working overseas, expanding your own horizons)...or even languages you speak or such.
Another comment is don't keep sending your apps so frequently. It can annoy them. They get hundreds of apps and if those that did not get in keep sending in apps with the same thing on them, they will ultimately blacklist you.