I guess you have think of the cost savings vs an actual fire too. $1.6B worth of property destroyed and a $55m cleanup project after the Boulder fires just now. That can justify a whole lot of $100 fire extinguishers even if they’re only marginally more effective (which it’s not clear that these are, just saying this is a problem you could justifiably throw some serious money at)
The comment about price was less about this application and more just to explain why Elide Fire Balls are not at all common in the real world... the company tries very hard to justify their higher cost but the advantages they point to are not especially convincing. Dropping them from above might actually be a pretty convincing use-case, but they're spherical and it takes seconds (Elide likes to say 3-5 but it seems often longer in practice) for them to melt through and activate. That means that in probably 8 cases out of 10 they'll roll away from the fire before activating, making them pretty useless. You can see in the Rain demo that they seem to have built up extra wood around the fire... I think this was to stop the balls from rolling off of the fire before activating.
In a drone system like this you're probably better off dropping the powder suppressant directly from very low. But that would require more complex custom fabrication of a delivery system. I think "Rain" just used the Fire Balls because of the simplicity of building a mechanism to release them, and not really because of any actual analysis of efficacy.
In their intended applications they're supposed to be hard-mounted where a fire is expected, or lobbed at a fire like an old-fashioned fire grenade... but the slow activation time just seems to rule that out as a good option much of the time. The only really compelling use case I see for them is mounting inside of electrical and equipment enclosures for automatic fire suppression, but there are other, cheaper products on the market for that use.
