I think it is a fair option, counterbattling at the moneran level. mb7 has been reported for years to offset invasions of cyano, bac v bac. theres enough reports of it working such that I don't think its a fluke, its just one of the tools we can use to win. the free option is rip cleaning, but its big work. the mb7/competing bac/nutrient sequestering all can work too but they typically require things to be bought and repeat dosed as needed.
even the rip cleaned tank can have it all over again if nutrient stores settle up in other areas unexported, or if lighting changes etc
cyano and associates are so common in our world some form of repeat will likely be required among most reef tanks, but for the clean running crew with good rock curing this lasts the longest...to either rip out the major sink for waste (sandbed) or blast clean it meanly which is what small reef aquariums can do easily without much work. find the detritus, attack the detritus is really a nice baseline mode for control of these invaders, where practical.