If my car has square tires on it, I could either shave the tires to make them round, or I could fix the whole problem by replacing them with the correct/best tires I can find.
The reason NRPE and other active check solutions are not good, is simply due to them being ACTIVE checks, plus the security factor. With NRPE types, the daemon is running on the remote system. Nagios has to login with the password, then it has to tell it what check to make. It then waits for the check results, then it has to process those results.
With a passive solution like nsca, everything is done for nagios without it's intervention. Periodically nagios reads the external command file, when it has the time to do so, and like magic, there is already the complete output of a service check. All nagios has to do, is to process that output so you can see it.