The main attraction for recumbent bikes is comfort. There's no hard skinny saddle between the rider's legs, no requirement to put weight on hands, and no craning the neck to see down the road. Most recumbent riders get into recumbents because they couldn't get comfortable on an upright bike. Additionally, many 'mature' riders who are coming to cycling in their later years are choosing recumbent trikes because they don't require balancing (easier to learn.)

A very few recumbent riders like me discover after converting, that a good racing bent can be stupid-fast in a way a time trial bike could never hope to be. The UCI realized this in 1930 and banned bents from competition in any of their sanctioned races.