They're not cool. They're fast and good for giving lots of shots in a situation where you need to get a lot of people in a hurry - especially if you're giving multiple vaccinations at the same time.
I got one of those used on me in basic training - a place where you need to vaccinate a few thousand people in about 30 minutes. Each one could do 4 shots at a time, and they had them in multiple configurations so you could get up to 4 in each arm for each "injection" station. We stepped through the line, and you got whatever shots you were missing in your records.
It hurts, like you could imagine a high pressure power washer with a needle-point burst with 4 heads blasting vaccines in your arms. It works, in the machine-like way the military works, and it is highly effective for mass vaccinations. So, I guess it makes it cool, but also it sucks like you'd expect 4-30 vaccines at once would suck.
She ran unopposed in the last election after claiming she was going to retire. However, because the local Democratic party can't get its shit together to run a candidate, she just filed her papers and extended her career of taking those free tax dollars and putting them in her pocket.