The second proposal I’d fully support. The amount of times I’ve seen, say, for i ∈ array in non-mathematical contexts over the years is pretty annoying, not only because it provides zero benefits for readability, but also in large part because looking from a new user perspective, many may not understand what ∈ even is and if it’s different from the keyword in.
It really is a social/cultural problem at the end of the day - for example, programmers writing in a language without convenient Unicode support would happily write um for micrometers and not have to bother with any of these questions.
I recall a post by ninjaaron years back which I didn’t think of much at the time but perhaps has some meaning now. The preponderance of mathematical symbols in a community presents a barrier to understanding for someone from a non-scientific background.