I've always thought of the "how to write grammatically correct code" style guides as being relevant to writing high quality code in the context of a team that m

I've always thought of the "how to write grammatically correct code" style guides as being relevant to writing high quality code in the context of a team that may onboard a new person or an internal transfer: they provide some baseline guarantee (insofar as the team honors them, of course) of the structure and formatting of the code. This reduces some amount of friction in a team. The benefits provided are largely context dependent (e.g. they'll benefit teams that expect to have a couple of senior engineers and many juniors on a relatively constant basis more than a team of experienced engineers in general), but I think having a style guide is important for any "large enough" engineering organization. I've also always insisted on including at least some loose guides to cover the "how do I structure a paragraph" cases. These generally are going to vary on a project by project basis, though, so they're going to be more vague as a rule.