I suspect that the success of iNaturalist is due in part to the egalitarian nature of membership. I certainly was encouraged to assist with identifications knowing that my opinion was as valued as anyone else’s opinion. I was also keenly aware of the need to identify with care because I carried an equal weight to others. All collections have their identification errors, and there are "…tools for assessing the data quality of each record,…"¹ Perhaps part of the secret sauce to the success of iNaturalist as a citizen science site is the egalitarian nature of membership as a citizen, both as an observer and an identifier.
I believe any form of reputation system would change the core ethos of the site. I also suspect that given the global reach of the site and the sheer number of users, any implementation would be sufficiently complex as to have multiple issues of its own, and many unforeseen consequences.