Some things are important because they’re unimportant. These things are not intrinsically important, but if not handled correctly they distract from what is important.
Content is more important than spelling and grammar. But grammatical errors are a distraction. Correct spelling and grammar are important so readers will focus on the content. Typos are trivial (more on “trivial” below) but worth eliminating.
When I was in college, the computer science department deliberately used a different programming language in nearly every course. The idea was that programming language syntax is unimportant, and constantly changing syntax would cause students to focus on concepts. This had the opposite of the desired effect. Since students were always changing languages, they were always focused on syntax. It would have made more sense to say that since we don’t believe programming language syntax is important, we’re going to teach all our lower division courses using the same language. That way the syntax can become second nature and students will focus on the concepts.
Grammar, whether in spoken languages or programming languages, is trivial. It is literally trivial in the original sense of belonging to the classical trivium of grammar, logic, and rhetoric. These subjects were not the goal of classical education but the foundation of classical education. We now say something is “trivial” to indicate that it is unimportant, but in the past this meant that the thing was foundational. Calling something “trivial” meant that it was important in support of something else of greater interest.
When people call something trivial, they may be correct, but not in the sense they intended. They might mean that something is trivial in the modern sense when actually it’s trivial in the classical sense. For example, unit conversions are trivial. Just ask NASA about the Mars Climate Orbiter.
For a day or two, make note of every time you hear something called “trivial.” Ask yourself whether it is trivial in the modern sense of being simple and unimportant or whether it could be trivial in the classical sense of being foundational.