From what I understand, you seem to portray flying out of small strips as a negative point but I would suggest it is in fact the opposite.
I did all my PPL training at Barton, near Manchester. I learned to land on 4/5/600m runways, where there is a lot less margin for error. You need to nail the speed and approach profile, whereas a long tarmac runway would be a lot more forgiving of a sloppy approach or high airspeed for example. Everyone I have asked unanimously agrees this is useful in honing your handling skills and I would say that this is most important during your PPL training. The other point is smaller airfields tend to have an AGCS or AFIS rather than ATC. The result is you are forced to build up solid situational awareness of what is going on around you, based on the information you receive, rather than slavishly depending on ATC to tell you what to do and where to go, and this again is another crucial skill to hone during your PPL.
The downside of course with a grass strip is flooded runways closing the airfield. My PPL skills test at Barton was cancelled 6 times as I happened to finish my PPL just before a month of snow and rain.