Why does a lot of research in astronomy prioritize the exoplanet search?

The search for exoplanets (particularly earth-like and life-containing planets) is one of the major priorities for the Webb telescope. More generally, it seems like this search is the source of much interest in astronomy over the last 2-3 decades. Why is this? I understand that part of the reason is that the area has seen a lot of progress, which is a justification in itself.

But in addition, is there any kind of exploratory document or statement of purpose about what the plan is if something is found? As in, what could it mean, where science/government would likely go from there? What new research/programs/missions it might lead to? And how it could benefit humanity?

These statements could be from NASA, other space agencies, various funders of these searches, and/or independent groups of scientists. I'm just interested in the big-picture intentions behind the search, if there are any.