Why, djbaxter? Why would business1.com be better? It describes what the business does, which is obviously plumbing.
Based on my research and testing, a .Plumbing domain would convert better on Google AdWords for less money (cheaper CPC) than an equivalent .COM domain.
Say you had 2 websites. Both same pictures, text, pages, etc. on both (assuming duplicate content "wasn't a thing"). Would the .com rank above the .plumbing website?
- it's true that the domain name doesn't matter, technically speaking. We know that, Google has verified it more than once.
- When you have a domain that includes your keyword in the URL, then it's more likely that your links are going to have your preferred anchor text.
- It's easier to get "plumbing" as a keyword into your anchor text naturally when you have plumbing in your domain name.
I've seen (and written case studies, publicly) that show that when a site moved from a .COM to a keyword rich new gTLD domain, they rank better. Especially for their preferred keywords, which are included in the URL/domain.