Yes, the film handling, especially with 35 mm film is a bit of a bother. I am thinking of making my own 120 camera eventually, but I am still gathering ideas.
With pinhole the bigger the better. that said who wants to lug around a 16X20. I find 4X5 nearly ideal. I don't bother with film but use photo paper as a negative, and then contact print to get a positive.
Advantages;
1. Being able to handle loading and developing under safelight.
2. Cheap. About 50 cents per print. (negative/positive pair)
3. Longer exposures easier to time.
4. No need to wait to finish a roll. Each film holder only holds 2 exposures
5. Can be processed and printed with very minimal equipment and chemicals.
Disadvantages;
1. Very slow, usually ISO 6~12, so get comfortable, could be awhile.
2. Contrast can be hard to control.
3. Poor latent image stability
Overall I find 4X5 to be the sweet spot in pinhole.