I don't care at all about whether or not a business as a .com domain name. I care about usefulness and utility. As long as the business shows up when I google them, I'm good.
For instance, the author's own web site is standupti.me. It's actually something I might consider trying out. But it comes across as someone's side project by a solo developer, not a company. As a potential customer, I might still get around to trying it out at some point in time, but I do have a slight negative connotation in that it might just disappear tomorrow. It would be 1000x worse for a larger enterprise customer.
If I tell my friend "Uber is awesome", their first step in using it will likely be heading to "uber.com". If it's not there, they might just end up forgetting about the recommendation. Existing customers would still be happy, but the business itself will have unnecessary trouble in being discovered.
Even if it's only 10% of people (it's probably a lot higher) who go to uber.com, that is a big problem for a business that's trying to grow as fast as possible.
However, from a usefulness & utility standpoint, do you care that when customers type the company's name in to their browser, they end up on their site? Do you care if first contact e-mails, etc. don't get delivered to the business? Even if you don't care about those things, don't you think other people might?