You got the acronym correct, but not the actual use. VFO mode allows one to set a frequency from the keyboard, and use the Menu function to set a PL tone, etc.
For a real example, last Saturday morning our District 1 ARES team was called upon to assist in locating a 12 year old autistic boy who'd wandered away from the hotel where he and his parents were staying while visiting relatives in the area.
Since the search area was so large, we chose to use an extremely wide-area 2m repeater, and I do mean WIDE area! It covers six counties in NW Indiana and a very large part of the Chicagoland area via two additional linked repeaters in Illinois.
As I did not have the N9IAA repeater programmed into my AT-D868UV portable, it took less than 2 minutes for me to tap in the frequency, and set the PL tone needed. After a quick radio check, I was prepared for the search. I was assigned to one of the 12 person teams to provide communications between the team leader and the incident command center.
Sadly, we did not manage to locate the boy, and they are continuing the search now along the Little Calumet River thinking he may have fallen in and drowned.