GAW:
Difference is One rov one shul is where it starts. It will explode very rapidly all over the country.
Re: Hiring a shadchan for a shul, there just aren’t enough shadchanim out there to hire one for every twenty girls. If it could be done it’s a start. (It would probably cost more to do that then to pay 150 each time the kids get to a 3rd date).
In addition this is NOT something the community should pay for. The people receiving the service should pay. (if someone can’t afford, well it’s like everything else in life. But why should it be structured that way initially.
FYI: many months ago I posted the idea of out of town communities hiring a shadchan for every twenty girls ages 21-25. That idea has evolved into the idea the OP discussed here.