Comparing the branding ability of companies with millions and millions of VC cash to sites attempting to fill very small niches has never really made much sense to me.
My webshop is small and in a small niche yet the most important search term for my website is my domain name, my brand. 30% of my visitors come to my website by searching for MY brand name and not for the brands I sell.
Having your own brand is especially and vitally important in the small niches. Being a "brand" does not necessarily mean that hundreds of thousands or millions know you. My brand is perhaps known to 15-20,000 people. But those are the ones that matter because they are my customers. Once people do not search for "niche-widget-brand" any more but for you - "nichewidgetaria" - then you have done it. The customers don't shop around anymore, don't compare prices, don't look at competitors special offers - they come directly to you because they trust you and your brand. Of course a brand is not just the name but it has to stand for something - for those things that distinguish you.
And what is true for shops is also true for normal websites. At least if you are in for the long run. The problem also is that "descriptive domain names" often shout "SPAM" or "Affiliate" from miles away. If I see something like "ultimatewidgetwebsite" I don't bother to click on it. For my own projects I'd prefer a fantasy name like "wapozoodle" to a descriptive domain name any day.