Most of us have long hair; you can simply clip it up so that all of your hair is under the steamer. My ends are the driest part of my hair, so I want them clipped up near the steam, anyway.
I would guess that some ladies don't need steam. Like, if you hair is already moisturized and you don't have any breakage or problems detangling, maybe there's not much room for your hair to improve. Some ladies on here do conditioner-only and never DC and their hair is doing just fine.
I have a large standing one. I use it inconsistently, but I think it's beneficial. However, I would not purchase such a large unit again. It's just too difficult to store.
.......I also limit my time to about 30 minutes. If I want to steam longer, I give myself a short break and then add more water. But, I think 30 minutes is good. I stay under longer sometimes because it's relaxing. Somebody mentioned forehead breakouts, which is interesting because I use a facial steamer to clear my skin. However, if you have sensitive skin, you should be careful with steam.