IMO if you have any algae eaters ie... Tangs or any other number of fish they will just decimate the macro algae. if they dont and it spreads it may overgrow your tank and compete with corals etc for space and light.
Yea i really don't have any voracious algae eaters yet... My lettce nudi will prolly like it but he can;t to much damage on it... Maybe I'll throw some in the back behind the rockwork and see what happens. Should I be careful on adding to much?