Using a play pen so bad?

We just got a playpen for our 5 month old. However I see so much negativity on reddit about using one and many people regretting it. The reasons we want to get one is:

• create a soft floor area for our baby to play and explore
• somewhere to keep him and his toys while cleaning
• have a space that feels like his as he doesn't have his own room yet
• a safe space to contain him for short periods while we work on baby proofing our apartment
• a place where it is easier for us to sit on the floor with him

We don't intend to leave him there alone unless I like need to pee or something, and we hope to keep it "open" (it has a little door), it's not supposed to be a little baby jail more just a way to divide the space. Is this a bad idea? Is there a better recommendation?

EDIT: Thanks for all the feedback. When I first searched I found mostly negative feedback, so let this be a positive search result from now on :) we will start using the playpen asap!