Baby jail—yes or no?

So we received a hand-me-down play pen from a good friend. Our gal is 6 months and on the verge of crawling. We live in a townhouse with lots of stairs. Our dilemma was do we create a baby-safe room with a gate or do a playpen in our most-used room (living room). We decided to try the playpen.

I’m curious because this thing is massive and while yes it’s nice to have a baby-proof space without having to baby-proof the rest of the house, is it worth it to keep this massive thing? What have others done?