Getting invested doesn’t mean your interests align. What’s best for your or the product can be different than what’s good for your boss, your company, your customers, or your teammates.
I used to document things in a way that would quickly get people up to speed, but was generally useless to current team members. Very useful if you where new or hadn’t touched the project in 3+ years, but no so helpful if you’ve been working on it for the last few months.