It is a fun environment and the community is very friendly and smart too. Its widespread adoption in finance is because it is a proven tool for processing the huge datasets that other systems cannot. If you have a business case for that, clearly it can be a worthwhile investment. Other industries are beginning to see value in leveraging their data sets and that's probably why after being in the business for 20+ years kx continues to expand their customer base; note they now have pharma and energy customers. Yes, there are difficulties involved in managing huge data sets, but IMO no other tools does it better than kdb+.
I've worked in many shops that use kdb+ and the ones who really benefit are the ones who bothered to get some training on it rather than those who just assume they'll wing it somehow. Kx themselves have been running great intro workshops for a couple of years now. Some guys at the next desk attended one and came back buzzing with excitement at how they now saw through the noise. So the take away is - if you didn't bother to learn it, stop complaining that you don't understand it. It's not difficult to get when it is explained well, but you're not gonna get it just by staring at it.