It's much easier for an attacker with few resources to go fishing for passwords, etc. over an open WiFi connection than it is for that person to somehow gain ph

It's much easier for an attacker with few resources to go fishing for passwords, etc. over an open WiFi connection than it is for that person to somehow gain physical access to an ISP and install a packet sniffer. So, the number of people who could conceivably be eavesdropping goes from a few (unscrupulous IT workers and law enforcement) to very many (everyone who can figure out a WiFi packet sniffer).