Repeatedly softening ice cream in the microwave
It's perfectly safe to do this, it's not great for the ice cream's consistency to keep warming it and cooling it as you'll start to get big ice crystals. I'd suggest you get a metal ice cream scoop and put it in hot water instead. 

If you have to thaw it to use it I'd leave it on the counter for 10 minutes instead of nuking it so you get an even thaw, using the microwave tends to melt one spot and leave another solid.