Large format is for those things that give you time. Landscapes, portraits - anything not moving much. I regularly backpack with my 4x5. What I will shoot there lends itself to that format very well. If the subject would look best on AZO or as a Kalitype and would be good as an 8x10 print, I will use my 8x10 camera. I really enjoy 8x10. I don't have an 8x10 enlarger and I love the detail and sharpness of the contact prints I make with it. Portraits and landscapes - things that do not require much hiking or movement.
Now for the other part of the story. A good fast handling lightweight medium format camera will get you those steet shots and spontaneous shots that you will not have time to get with a 4x5. Smaller and lighter will fit fine with you anyplace you go. An equal amount of my photographic time is spent with a cheap used Bronica and a monopod. With careful shooting and good film and developer choice, I can make photos that will hang proudly on the wall next to shots taken with the 4x5. I make my camera choice based on this: shots that will be no larger than 4x6 - 35mm camera - point and shoot - Canon Rebel. For anything really worth taking a photo of but I can't set up for it - The Bronica ETRS. For shooting where I can set up - The 8x10 if I can drive there or the 4x5 or Rollei SL66 if I walk there or need to enlarge it.