No, but ignoring these basic project conventions can lead to issues when another developer tries to work with the file, specifically around charset and line endings.
These are all sensible things to enforce (with the exception of tab_width, which is actually a display preference). Subjectively, other things are mostly flexible.
There are more properties listed in the complete list (link is above the short list), mostly about parenthesis and braces. I guess they aren't listed in the main page because they are language-specific.
Same goes for new line at the end of the file, how do you know ALL files of this type are meant to end with a new line or not?
Inference doesn't completely solve the problem that editorconfig solves. That said, if you don't want editorconfig then don't use it. If you're working on a project that uses editorconfig, feel free to ignore it - as long as you adhere to the code style of that project. editorconfig is simply a tool to help you adhere to a project code guidelines.
That's cool, but that's one plugin for one editor - editorconfig is a simple plugin with a very wide range of support to solve the problem it solves.
Linters and formatters are great for enforcing code styles but they tend to be per language and require more configuration, shy of ripping off an existing spec.
If you don't want to go the whole hog and only need some basic constraints then editorconfig is easy to throw into a repo root.
"ANSI" hardly counts as a default. (ANSI is MS's incorrect term to mean the system's encoding, which can be any of a number of different character sets.)