Apologies if this is isomorphic to an existing question.
I ask because it seems like there have been some recent questions that clearly belong better under the tag "Banach algebras" than "Banach spaces", yet where adding an "operator algebras" tag seems to stretch the point a bit far. A quick search for "Banach algebra" on the main site throws up about 40 questions containing the phrase, many of which might benefit from the tag being used.
Is there any reason why there isn't a banach-algebras tag?
Here are some candidates where I think the tag is both appropriate and useful:
Why is $\ell^1(\mathbb{Z})$ not a $C^{*}$-algebra?
a question about invertibility of Banach Algebra
How far is a Banach algebra from being a multiplicative group?
Why is $GL(B)$ a Banach Lie Group?
Closure of the invertible operators on a Banach space
Prove that $\sigma(AB) \backslash \{0\} = \sigma(BA)\backslash \{0\} $