Some townhome owners decide to rent their units instead of selling them. 

In some cases the owners haven't lived in their home long enough to gain any equity & would have to bring money to closing. Selling their home isn't always the best option. However, sometimes they have to move due to job relocation or an additional family member.

Keep in mind that owners who choose to have their home on the market while inhabited by renters won't always work out so well. Many renters don't want the hassle of showings. They won't clean up beforehand or may possibly say no to a showing. 

It is possible to own one home and rent it out and buy another. The home may raise in value over time!

Remember to check your bylaws...some associations do not allow for units to be rented out!