Cant help with your second question, but as to the first.
I like them.
I recall as a kid I liked to play with puzzle toys like those; sorting the tiny squares about, mixing them up, then putting them back where they should be.
If going on long car rides I would take them with me, since I did not need a sister to play with it.... and they (my sisters) were not very much fun to play with on long car rides.
IMO they were Cool short term toys back then.....
As collectables today, they are not all that rare, or even much sought after by most collectors, though some collectors will look for them especially TSR completists.
I once had a couple of them and they went with a large lot I sold several years ago.
Dont miss them nearly as much as many other things that went in the sale.
I miss the everyday regular TSR
RPG modules far more, now that the grandkids play D&D....