Thats probably the best way, you could cut the interval a little (maybe damaging once every second or something, dependand on your map. But honestly, I think even every 0.0625 would work just fine). If you do not care about stacking damage, you could just take the damage effect and give it an area. Otherwise, do it like psi storm, persistent or behavior at the structure -> periodic search -> apply behavior -> periodic damage.
Overall, the performance of the data editor is very good, should not be a problem. Any other solution would most likely be inferior, for example when involving triggers or something.
Thats probably the best way, you could cut the interval a little (maybe damaging once every second or something, dependand on your map. But honestly, I think even every 0.0625 would work just fine). If you do not care about stacking damage, you could just take the damage effect and give it an area. Otherwise, do it like psi storm, persistent or behavior at the structure -> periodic search -> apply behavior -> periodic damage.
Overall, the performance of the data editor is very good, should not be a problem. Any other solution would most likely be inferior, for example when involving triggers or something.