Yes, but it's also a demonstrated fact that people are more likely to make exercise a regular part of their lives when it is integrated into their daily routines. Additionally, there appears to be some evidence that more frequent smaller bursts of exercise may actually be more beneficial to people's health than going to the gym and working out harder only a couple of days a week. A big part of the problem we have with sedentary lifestyles is caused by the fact that exercise is not routinely integrated into people's lives unless they choose to seek it out for health benefits, as a hobby, etc. The path of least resistance is often simply to not exercise, while biking for transportation breaks that pattern.

And everything in life has "risks". Walking down the street on the sidewalk has a risk of death that is close to on par with cycling. Exercise of any kind has a small risk of death from heart attack, overheating, dehydration, etc. Constantly worrying about risks without weighing them against the benefits (both in terms of health and general psychological well-being/enjoyment) is silly. We don't live our lives in empty rubber rooms, so we have to accept the possibility of death or injury. Living means taking risks.