Whilst I don’t disagree with Robert’s answer, to answer your question about whether pulses can be counted directly on the RPi, yes you can, for example in this Directly connecting to Optical Pulse Counter with RPi? thread. I have used the same or similar code to count pulses from a generation meter’s SO contacts too.
Although if you are receiving RF data and need the rfm69pi there anyway, there is probably little to gain by shifting the pulse counting to the RPi.