While I still feel that clubs mostly exist to provide extra ice time, clubs are partly social. Figure skating, if you aren't in a synchro club or production team, can be a lonley sport.
18 people would be a moderately busy freestyle, busier than what you already have - but on club ice, some pre-teen and early-teen girls may congregate by the hockey box, not skate, and not take up much ice.
Clubs also represent a way to organize tests and competitions. Are those already available within 1/2 day's driving distance of your area?
For a few of the kids, they may represent experience organizing things, and community service, that they can put down on college applications.
Depending on how your rink handles things, club ice could represent a major financial obligation. If not enough people come, who is left with the obligation? In addition, it represents a major time commitment. Most USFS[A] clubs expect parents to volunteer a substantial amount of time, and there are officers with extra obgligations.
In the U.S., for the USFS[A], there is "SafeSport". https://usfigureskating.org/content/Safesport%20FAQ.pdf http://www.usfsa.org/content/safesport%20handbook.pdf
I.E., there are all kinds of time and financial obgligations towards safety, aimed in part at making sure that everyone is provably
innocient of abuse (not just actually
innocent), and has done everything they could to prevent abuse of kids by other kids as well. E.g., Required training and test passage; you can't have just one adult in a room with minors; you sometimes can't have kids in a room with other kids, or sometimes by themselves, unsupervised by adults; you can't transport kids not your own without all kinds of paperwork; all adults coming into contact with other people's kids must be properly vetted; reporting requirements; insurance requirements; etc.
If you already have a USFSA club at all, even without club ice, many of these things already apply. But club ice represents one more time set that these things apply, and perhaps an increase in the number of adults who must be vetted (and registered and insured?? I'm not sure.) and mutually supervised.
All in all, if you already have 25 hours a week of freestyle sessions, it's a lot to expect. (I wonder if ISI clubs represent much less work and requirements for the parents. And I assume that most other countries have few such issues.)