I was reading an article about this sumo.com purchase. I think it is quite ridiculous to spend that much money on a domain name. But of course, I don't have it and probably never will. Here is a link to this article: https://www.entrepreneur.com/article/288629
Well, the article raises valid points and especially when it talks about Mark Zuckerberg. As for the amount of money used for the purchase, I'd probably say you can only spend what you have especially when you have projected that you can have an ROI, sooner or later.