I cycle primarily for enjoyment, any health benefits are a welcome addition but are not my primary motive.
If the primary goal is health benefits, then there are several other exercise types that are more efficient (time spent for benefit received), and less dangerous. e.g. indoor rowing, indoor cross-country ski, eliptical machine, etc.
If cycling is what gets you to exercise, then fine - but other exercises are better for many people.
Endwell NY USA