If you like a thing, it feels natural to tell others about it so that they can also benefit from it. There is no ulterior motive here. Sure everyone in the community will benefit if jj becomes more popular, but it's not like they are trying to sell you something for money. If you don't like it, that's fine, but if someone is facing similar problems to the OP then they will benefit. Almost everyone I've shown jj to at work has converted because it solves the same problems for them as it did for myself. Of course, not everyone has those problems.