Cygwin is a lot bigger and more time consuming to install. Putty is what? Half a meg and you're done? Much much much lower barrier to entry. There's also the i

Cygwin is a lot bigger and more time consuming to install. Putty is what? Half a meg and you're done? Much much much lower barrier to entry. There's also the issue that in a corporate environment, having a much smaller attack surface is greatly preferred. Trying to get something like Cygwin past the security dept in a BIG company - quite challenging.