Is it cruel to make our daughters share a room when we have an extra room

Our daughters are 6 and 3. They share a room and the other room is my husband's office. He's a teacher so he uses that room for grading and lesson planning. I feel like it's cruel to force them to share a room when we have the extra room but my husband said they aren't complaining. They play together and when they're older and want their own rooms he will turn his office into a room for them. Is this cruel?