Depends on where you ride your bicycle.
In the US, bicycle deaths are at 79 per billion miles src. In the Netherlands, this is 17 per billion miles. src.
Note that the Dutch take much more risk when cycling. It is normal for young kids to cycle to school and sports unsupervised. Bicycle helmets are very rare. Despite that “reckless behavior”, cycling is quite safe here. Having dedicated cycling infrastructure really helps.
Security through obscurity is a very valid way to secure something. It shouldn’t be the only way of securing something, but it can be a valid additional layer.
The knock sequence is a secret, just like a password. It may not be a particularly strong secret, but is is strong enough to keep out casual attackers. You’ll still need additional security, but sshd is well equipped to provide that.