This was a terrible idea from the start. And I've been hearing from lots of folks that the influx of "users" attracted to scammy stuff like this have been harassing other Keybase users via DMs. Congrats on ruining your service, Keybase.
I went from about 25 followers to over 50 in approximately a month, after being there more or less from the launch. Those first 25 were largely people I've personally met in real life. The rest are entirely fakey.
So yes, it's had an effect here as well.
They should have just given coins to existing active keybase users. They would have had healthy increase in users based on regret and fear of missing out again.
This has just forced them into coming up with a solution now rather than waiting a few more years when the network's larger.