"So if I use the unit that has +3.3 and +5 Vcc out and use the +5 Vcc out and the Rx/Tx that measure under +5volts I should be ok?"
Yes.
"What the heck is the purpose of having +3.3 Vcc if Rx/Tx does not change to 3.3 and remains under 5?"
Some devices need 3.3 for Vcc but have 5V tolerant IO pins.
"I am trying to figure out why this USB to Serial was made this way and how it could be used practically!!!"
Ignore the 3.3V.