This overhyped description coupled with on-by-default analytics suggests to me MeiliSearch should be dismissed regardless of potential usefulness or technical merit.
"We send events to our Amplitude instance to be aware of the number of people who use MeiliSearch. We only send the platform on which the server runs once by day. No other information is sent. If you do not want us to send events, you can disable these analytics by using the MEILI_NO_ANALYTICS env variable."
This is already pretty invasive - it discloses activity, number of machines deployed, IP address which identifies location and often organizations and individuals (and which is considered protected personal data per the GDPR afaik).
> The privacy of the users is kept.
No it isn't, see above - even as the authors you don't get to decide what data does or doesn't infringe upon the users privacy.
> It just serves us to know if our work is being used.
This is irrelevant, if you want to condition the use of your work on being let known where and how it is being used then license it accordingly and abide by the applicable laws.