You may be an excellent and perfectly competent developer in your day to day job, but by not knowing (at least certain) terminology for your field, you are lacking a certain degree of professionalism and are certainly restricting yourself in the broader field as you are lacking the ability to effectively converse with others in it.
All different fields have their own set of terminology and at some level it is arbitrary as to what things are called, but when it comes to communicating with others, it is absolutely essential that you all use the same terms for things. When people aren't familiar with standardised terminology for their field, at best they battle a bit when it comes to communication, at worst it leads to a misunderstanding and the wrong thing being done.
Even if your methodologies are exemplary, it is for nought if you are applying the wrong ones simply due to a misunderstanding of what was asked.
My girlfriend is in the process of acquiring a project management certification (PRINCE2) and while part of the certification covers methodologies, an arguably more important aspect of it is the terminology, in particular, the names of different roles that people are assigned to on projects. This is important because she works in a consulting firm and all their big clients expect the consultants to be familiar with these names of roles so that in client meetings, the client could just mention a role name, and everyone in the room will already be on the same page as to the responsibilities and expectations of any person with that role.
At one of my previous jobs, developers were given training on and are expected to at least know the following above and beyond "knowing how to program in general":
- - GOF Design Patterns (at least their intent and how they conceptually solve a given problem)
- - OO Terminology
- - Data Structure Names and what kinds of problems they are appropriate for
And other stuff of course. It of course helped us day to day solving problems, but I imagine that it also helped all of us more readily absorb information at conferences too.