I mostly use it myself for looking up stuff adhoc without a SQL query. No plans to kill it, but it does rely on relay aggregation which has been a time consuming to maintain - mostly spam mitigation.

The seen by data only listens to relays and doesn’t crawl, so it’s most accurate closer to initial event broadcast time. And relay aggregation varies between 120-180 or so.

I don’t know if anyone else uses it for anything serious, but it does have rate limiting.