The reason people remove them is that the FIAV can go bad. It is normally open and the warm coolant melts wax inside it, which expands and closes the valve. When it goes bad, the wax leaks and never manages to close the air valve.
The net result is a higher idle speed when cold, dropping down to normal as the engine heats up. If you just remove the lines and block them off, or if the valve is bad you will have an abnormally high idle (~2000 RPM instead of 850RPM). If you don't, then the previous owner blocked up the valve and everything is fine. If this is the case, since you live in a warm area, everything is fine.
If you've got high idle, you have two choices - either hook up the lines (one goes to the small branch on the main water pipe, the other goes direct to the T-stat housing - you can get the hoses from JNZ or anywhere else that sells OEM or replacement parts). The only issue is that if the valve was actually bad, it won't fix the problem.
The other option is to block off the valve, which there are several methods to do - search around for FIAV Block Off.
