"Paying designers instead of paying Facebook Ads" sounds good! What kind of rates are you paying the people who're actually doing the work, though? And what's your plan for when the funding runs out - are you gonna follow Uber's path and start shaving more and more out of what the designers get?
Aaand... if a client and designer who you matched up decide they would like to pursue a working relationship outside of your app, without paying you your cut for future work, do you consider this a success, or a failure?
Aaand... if a client and designer who you matched up decide they would like to pursue a working relationship outside of your app, without paying you your cut for future work, do you consider this a success, or a failure?