I originally learnt on an antiquated board and rig which most people would have just thrown out. It cost me a whole $100.

It was the best 100 dollars I spent in the previous 30 years.

It took me all summer just to be able to sail out and back without falling off, no gybes, no water starts, no harness, no foot straps.
It was one of the best summers I had on the water after many years of surfing, all for about one hundred dollars.
I then 'splashed out' on another slightly more modern junk rig for a whole $300 and had the most fun ever for three or four summers getting water starts to work, getting into the footstraps, perfecting catapaults to look entertaining, and eventually getting the gybes to work reliably well.
In spite of it's antiquity, and mine too, it was still almost as fast as a lot of the better rigs.
Best of all, it sailed in quite light wind and could glide through a lull, even though it was small.
Fun per dollar,.. exceptionally good.
Since then I've spent thousands on boards, sails, carbon masts, new booms, harness,.. etc etc and although they are mostly ok, I don't think I have ever come close to the fun per dollar ratio that I got out of my original junk rigs which most people would have thrown away.

The thing about junk rigs is you can cane them mercilessly because even if the thing explodes, it cost you nothing.
I caned these to death and the boards never broke even though I sometimes did.

I would never say a bad thing about junk rigs.