My spouse and I have lived in our house for five years, and in that time, we've basically played Jenga in nearly every room. It's almost like a design challenge to see how many spaces can serve dual functions: Can we make this room into a gym? What about a gym/office? What about a guest room/office? Right now, we are transforming our office/gym into an office/guest room (the Peloton now lives in the makeshift sunroom downstairs).
There's no denying it - having a spare bedroom is a luxury. Not only is it a place to host guests, but it's also extra square footage to play with. The room can transform into anything, and that freedom can be a blessing and a curse. The multifunctionality can lead to a cluttered space - especially if the room is cramped. However, the IKEA HEMNES daybed, an item that's been getting a lot of praise on social media, helps to reconcile that.