This is what I felt about Neeva, too. Metered searches meant I only used it when I “needed” it… By which point I was mired in search results and focused on my Google Fu and completely forgot about Neeva.
I get that it costs money to run, but they needed a long free trial to get me hooked, then a reasonably priced unlimited tier. I was never going to use a site that restricts my search volume.
iirc, their trial tier was 100 searches total, or something like. I could never adequately test it so I never converted to a paid user.