People don't use it because it is terrible. I had to manage a 5-node Mongo cluster as recently as 2 years ago, and I still drink heavily because of it. It was a data roach-motel - your documents check in, but they never check out!!!
Everything ran fine, until it was time to fail over - and the company had a 'full failover every quarter' commitment. Every single time we went from the 2-node primary site to the 3-node secondary, all he would break loose. Bad writes, lost partitions, it was a new 'thing' every quarter. Mongo, in my limited experience, was a terrible platform and I recommend everyone who is thinking of implementing it to run screaming. It accepts data SUPER fast, but so does /dev/null.
Everything ran fine, until it was time to fail over - and the company had a 'full failover every quarter' commitment. Every single time we went from the 2-node primary site to the 3-node secondary, all he would break loose. Bad writes, lost partitions, it was a new 'thing' every quarter. Mongo, in my limited experience, was a terrible platform and I recommend everyone who is thinking of implementing it to run screaming. It accepts data SUPER fast, but so does /dev/null.