For me, it's a 20+-year old analog watch with no frills whatsoever.
The only "aviation feature" I'd be interested in is some sort of dual time mechanism for UTC. Not necessary, but handy sometimes.
Remember that you are only going to need to do timekeeping for your x-country legs. And on your exam those have a margin of error of +/- 5 minutes. Timed turns, holds and so forth require more accuracy but are not part of the PPL syllabus.
"Aviation" watches from e.g. Citizen and Breitling are not so much "functional" but "lifestyle". As far as function is concerned, your girls pink £5 jobbie will do just fine until well past the PPL level.