I don’t think you’d use it as a general search engine, but more as something integrated into your site. So “Dog Buddy Magazine Online” might use MeiliSearch to let visitors seek out articles by breed, puppy or adult, and other factors relevant to the sites readers.
License: MIT. See https://blog.meilisearch.com/oss-paradigm/ Paid plan: I haven’t seen it, but I just discovered the software and site a few minutes ago; maybe they’re charging for support.
Anyway, it is interesting. They seem to compete partly with “ElasticSearch”:{https://www.elastic.co/elasticsearch/} (and maybe a little bit with #YaCy’s stand-alone mode).