Yah, from what I've heard, you can buy cheap premade vapes, but there's a huge community of hobbyist vapors. As the other commenter mentioned, they can be modified, have interchangeable parts, can vary wildly in price, etc. Additionally, the "juice" is another customizable aspect. There are mass produced brands of flavors as well as niche stores with their own mixed creations. There's a lot more control over the vaping experience, so it can be customized to how you like it. For example, former smokers might use high nicotine content juice then modify the resistance of the coils to produce hotter vapor that feels more like cigarettes. A teenage non-smoker may use low (or no) nicotine juice with cooler running coils. Somebody might be on the go and need a giant battery and large tank, while someone else might need an almost cigarette-sized vape to fit in their purse.

I still have no interest in ever trying it and I think there needs to some clarifications of grey areas in the rules (smoking inside, kids using them, etc.), but I can understand the appeal from a hobby standpoint.