When it's about actually adding 2 integers - sure. But when it's about the relational algebra - does it? Can you actually just write ⟖ instead of RIGHT OUTER JOIN when querying a real database?
Also, I don't really understand why is it supposed to be hard to do in a text editor.
I'm not sure what arbitrary symbols* as operators gets you. "It's built on concepts from relational algebra" does not mean "it must literally be a 100% compatible relational algebra mathematical engine." That is not the purpose of an RDBMS, and the purpose of relational algebra isn't to find a use for sigma, pi, and rho. Nevermind how eye-bleeding the difference between ⟖, ⟕, ⟗, ⋈, ⋉, ⋊, and ▷ will be in a sea of table and field names.
(* Yes, I know those symbols are the conventional relational algebra symbols. They were still chosen arbitrarily as notations built on top of the multiplication symbol borrowed as the Cartesian product symbol.)
I just really hate seeing/typing RIGHT OUTER JOIN when it could be just ⟖. It feels like it takes me a microsecond to read the symbol, translating the glyph straight into its meaning in my head instead of subvocalizing it first and thinking what does this mean then. This takes way more time and struggle with the words. Also the whole query consisting of many such words becomes too big to read easily or split into logical parts visually and also looks ugly from the purely aesthetical point of view.
To me sea of the SQL language elements represented with words intermixed with table names and other words into one uniform ocean of words seems at least no better than the names intermixed with the distinct kind of symbols (each of which I recognize instantly).
