My understanding of string theory is that even if you understand it as a tool for mathematical formalism, it's actually not all that effective. Not that quantum

My understanding of string theory is that even if you understand it as a tool for mathematical formalism, it's actually not all that effective. Not that quantum field theories are all that easy to work with, but my understanding is that their string theoretic counterparts are downright intractable. It's kind of interesting when you actually take a closer look at the PR of string theory. There's lots of bombast about it being a candidate--the strongest candidate--for a theory of everything, but when you try to actually press for what that theory of everything, it ends up being "well, we don't actually have one yet." To answer your "why" question more directly: string theorists themselves have been very loudly proclaiming for decades that they are the One True Path™ to a theory of everything. This isn't coming from incredulous science journalists trying to summarize a hot field of study for the general public, this is the messaging from the leading researchers themselves, and they've been doing it long enough that a knowledge of its existence and its role in the theory of everything is firmly embedded in public consciousness, even if all details beyond "tiny strings" and "something something extra dimensions" are stripped out. So we should hold the field to its own standard of why it should exist.