I've been doing some preliminary reading on trademark law, and I see that a trademark with the USPTO isn't necessary to defend the uniqueness of your new brand name or log in court.
The USPTO gives a list of reasons why you'd want to register, but with my project in question, I don't see many of them as applicable to me. I've searched their database and it comes out clean, and apart from a squatter on the .com I have pretty much unlimited domain choices, so I'm pretty confident that we won't be stepping on someone's toes. We're in a niche industry so the probability of knockoffs will be low for some time.
Which leads me to the question. Is trademarking always done by everyone or is it only done by the bigger fishes? Is common law enough to protect a trademark? If you/your client wants to trademark, what is the most common reason cited? Is it more about creating better legal protection for you, making sure you're not infringing on someone else, or something else completely?
This might have been a better fit for Startups, but I see that doesn't exist anymore. I'm a designer looking into trademarks, so I'm hoping others have as well and have some insight!