"Tow mode" or more accurately Tow/Haul Mode is a transmission mode that has been in trucks for years. Normally engaged by pressing a button on the end of the transmission lever, it changes the performance characteristics of the transmission, mostly how/when it shifts, to make it more appropriate when towing or hauling a large load.
Do you need to use it? No. Should you use it? Yes, when it assists your driving situation. Some people go into Tow/Haul mode in their MH as soon as they start it, others never use it.
I don't use it even when towing when I am accelerating or driving on fairly flat roads. I will use it when I am coming to a stop as it causes the transmission to downshift more aggressively and assists the brakes. That is why it should always be used in mountainous driving, plus you can force a downshift by tapping the brake.
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad
2020 Chevy Colorado Z71 Trail Runner Alternate Toad