IT people try and "trip you up" because we've been burnt so many times in the past with systems that don't do what is promised by the sales people, don't integrate well and who stiff you during the implementation phase.
HR people are some of the worst because everything is super secret and they don't want to get IT involved, then they go and buy a system that lets you insert a carriage return into the phone number field and produces CSV files that don't have primary keys for data extracts.
Everyone walks on eggshells around HR for "compliance" stuff. Anecdotally, I've not see a whole lot of compliant practices in the stuff HR wants. The high end HR solutions tend to enforce it, but there are always amazingly bad home grown tools sitting around to allow you to "pull a list of all our employees and all our data to a CSV" and then you find out the person converted that CSV to a google doc...(I've not seen anything that combined all these steps exactly this way, but I've seen each of these steps. The more legacy the tools, the worse)
And yet a bunch of them chose MongoDB (over something else, not just over RethinkDB.) Was there some point in time when it was the best option for a lot of people?
They were a fairly early entry into modern document databases. They offer sharding/mirroring, and have a really simple, relatively nice interface. In the end, they're a good (enough) fit for a lot of use cases. While RethinkDB imho is absolutely better, market share entropy counts for a lot. ElasticSearch is a similar product in the end, with lower consistency guarantees, that is another good fit for a lot of use cases. Cassandra (C*) is also a good fit for similar use cases, though more difficult to work with, it's also more tune-able to specific needs.
It really depends on what you need... Every non-sql database tends to sacrifice something for some performance gain... RethinkDB is as close as I've seen to one without sacrifice.
Yes, there was a point it was clearly the best option. Qualitative it was easy to understand. The mongo Cli looked exactly like MySQL. And it's single node performance was decent.
CouchDB was super slow. Cassandra was amazing but a bit confusing. MongoDB made sense and worked.
HR people are some of the worst because everything is super secret and they don't want to get IT involved, then they go and buy a system that lets you insert a carriage return into the phone number field and produces CSV files that don't have primary keys for data extracts.