Obsidian's licensing makes it immediate non-starter for me and I would imagine the same for most people who would want to use it for work, side projects, or anything they hope to make money off of.
What is the problem you see? I am interested why i should be cautious. It seems like offline app that uses .md files. And the authors seem legit bootstrappers with quality projects behind them.
The free license and the one-time purchase license do not allow for commercial use. You would need to purchase their Enterprise license to use this commercially. Is it expensive? Not really, $50 a user per year isn't necessarily expensive when considering price alone but when compared with other alternatives in the space I'd rather not deal with a yearly license. I used Obsidian Beta up until they released their licensing.