I've also used them many years ago, they're okay if there's a place available to anchor the foot and it doesn't matter if it leaves a divet in whatever it's sitting on. Maybe useful if you're working on heavy construction steelwork or structural anchor bolts.
Nowadays the newer generations of air and even cordless impact wrenches have made them mostly redundant, even my 18v Bosch impact wrench can apply over 1300Nm of torque and it's by no means the biggest or best. Also the mechanism of impacting is more conducive to seized or stuck bolt removal than just pure smooth torque.