Today we think of film cameras as 35 mm but film comes in many sizes and they all have there uses.
I still regularly use "large" format (5x4") and "medium" format" (120 roll film) cameras as well as 35 mm.
The different formats suit my different moods, one day I will revel in the slow, measured pace of my 5x4 field camera, on the next day it will be too big and too slow.
Then 35 mm will give me the speed, the flexibility and the raw edge that I want.
My main criticism of 35 mm is the enormity of every manufactures "system". We MUST have two bodies and ten lenses if we are to have any chance of taking a good photograph.
Less is more. All the time we are worrying about which lens to use or which exposure mode to set we are not taking photo's. The single most important thing we must do if we want to take good photo's is TAKE MORE PHOTO'S.
Even if our technique never improved we have a better chance of catching a great image if we take more. But by default our technique should improve as well.
I taught myself photography and I started with a basic camera. I used cheap transparency film and when a roll was processed I would sort the images into what I had wanted and the failures. Then I would analyze the failures and understand why they had failed. Then I would consider how the good ones could be improved. The failure pile slowly got smaller.
Eventually I was confident that I could shoot 36 images and they would all be what I had "seen". That did not mean they were good pictures but it did mean I could "see" the picture. Then all I had to do was get better at seeing more good images.
Now was the time to start exploring other lenses and other cameras.
I still find some of my most satisfying expeditions are when I carry just one camera and one lens, it makes me really focus on finding the images.