They aren't "useful as a side effect" they are useful because no-one else is willing to spend the amount of money the military is. No-one else spends hundreds of thousands of dollars on equipping high school drop out employees.
That's not to say that military doesn't have its uses, but if public benefit is your main goal then it almost assuredly would be better to create some type of agency or organization that was explicitly tasked and organized in such a way to meet those goals.
Yes, the internet was technically a military project in that it came out of (D)ARPA, but they seem to work a lot on interesting civilian projects that might have military spinoffs rather than the other way around.
That's rich. I think any agency could do amazing things if they had the budget the size of the military budget. Their amazing things wouldn't be "blow shit up first, let people share cat pictures a distant second" though.
Priorities, man.
95%+ of the work done is thrown away. I'm not talking about cutting edge R&D projects that happened to not work out, but literally work will be done and then never evaluated and throw into the trash. Agencies have so much money that they need to spend that they will have no idea what they want and will just throw half a million at you to go do whatever you want for a year. Then they will look at a powerpoint of what you did for maybe 20 mins, nod their head and scratch their chin and then pretend the whole thing never happened.
The Phase I to Phase III ratio has go to me like 100:1
But, unfortunately, what too many of today's software engineers are working on are apps that hardly anyone needs. "It's tinder for cats". Stuff like that.