S.
My advice is that the playhouses are fun, but your MIL is probably right. They never want to play with these things once they have them. I have had a playhouse, a pirate ship, and a slide with tunnel, and a zoo, and an activity garden. I could really keep going. When we moved recently I chucked everything but the pirate ship. We use it to store toys in. Ultimately, this is your decision. I would still probably get one.