Eddie explains the difference.
Software firewall, depending on software, can be hacked by other software.
The Hardware Profile, on the other hand, when told not to even turn on the NIC card, prevents *any* intrusion. Period.
And besides the above, the Software firewall situation does indeed chew up CPU cycles, possibly bits of RAM resources as well, and we need all we can get when making music by streaming to and from disk drives.
--Mac