I don’t publish anything on Thai food before running it past Friend of the Food Chain Leela Punyaratabandhu. In English, no one is writing more authoritatively on the subject than she. For readers of her blog SheSimmers this has been evident for years, and it was only cemented with the publication of her first cookbook, Simple Thai Food, which was a come-to-Jesus for anyone familiar with the broad array of disparate dishes that seems to appear on the menus of Thai restaurants everywhere in the world—except for Thailand. 
You’ve published persuasively about the street-food controversy in Bangkok, and the book coming out right now seems so timely in that context. Suddenly here’s this document underscoring everything you’ve ever said about how there’s so much more to Thai cuisine than street food. And it illuminates how much of what’s been published in English enables that shallow attitude about Thai street food.
Then again, back then, even though the materials existed, the idea of packaging them into a book about the food and the food culture of Bangkok did not. That idea emerged only after I took a long look at the things that didn’t make it into Simple Thai Food and saw clearly what they all had in common, which is that they represent my life not just as a Thai but as a Bangkokian. So it all worked out in the end, and I came to see that the materials that I wasn’t able to put in Simple Thai Food actually fit better in Bangkok, which is a different book, written for a different audience.
I ran the final recipe list by my friends and relatives, and one of my aunts said that looking at the dishes in the book was like looking at the people at her wedding party: a group of people, all in one place, who came from various stages of her life and from various places she’d been. They all were meaningful to her in different ways, and looking at them she saw her life in its totality—from the beginning up until the present time. I wasn’t aware I was doing that when I finalized the recipe list, but I have to agree with my aunt that, in the end, looking at these dishes really does give me the feeling one would have of seeing the people one has known and loved all one’s life who have crossed one’s path in various ways and in various places. As a born and bred Bangkokian, when I look at them, I too see my whole life from the beginning up to the present time. 
But as far as the genesis of the batter-fried version, my theory is that it started out like most previously nonfried dishes that are now deep-fried, e.g., crispy papaya salad (also in the book). And that is more of a way for restaurants to hide the lack of freshness of the main ingredient (kind of like how you slice up stale bagels to make bagel chips) than a way to demonstrate the spirit of inventiveness. (In some cases, it could also be a way to hide the lack of cooking skill, because it’s easier to deep-fry something to a crisp than to create something with multiple complementary textures.) And when the idea initially proved popular among Bangkokians who grew up with Japanese tempura and American KFC, it took off and spread.