I wouldn't call it a fascination but people like new things. Until recently Stern was the ONLY one producing new pins. They have chosen some great themes. Game play is fun on some of them.
For many of us we have been playing TZ, MM, AFM, TAF, etc. for quite a long time and they are still fun but you can only play them so much before they get old.
And now with more new pins being made people are excited about more choices....plain and simple.