Obviously it's not for everyone, but there are a huge amount of benefits to joining a club.
Diversity of routes...
A challenge...
A route into racing...
An opportunity for velodrome/track riding...
A new social circle...
To increase fitness...
Camaraderie...
Unlimited source of assistance and advice...
Improved cycling competence...
You can be as social or as unsocial as you like - you don't have to chat while you're moving but other riders will make an effort. You don't have to stop at the cafe after but it's often fun to. You don't have to go to social events but you tend to get out what you put in.
As
@Rob3rt says, there's no harm in giving it a go, in fact most insist on at least 3 trial rides before committing.