"need" isnt the issue.
You dont "need" another Mod. You "want" another Mod and are looking for the justification.
I dont "need" any more mods, nor boards, nor batteries. So why am I doing the (not to be mentioned) deal in the Classified section. It has become a hobby, an obsession, and a compulsion. It supports my addiction to nicotine, and my desire to "create" things.
As for price, the market has reached the point where DIY is not a $$ saving proposition anymore. Decent Mods can be had for less than the price of the parts we buy. Alas, I think the ones I build are better, but really its just a creative outlet. I like to create things, to hack things and make them better. Not only vape gear, but espresso machines, computers, and all sorts of other gadgets. "Creating" satisfies some inner need in my soul. "Creating" that also satisfies my addiction to nicotine is even better.
Plus, it keeps me off the streets........
IMHO, the DNA 75 is good for those who want/need replaceable batteries, or are trying to get Evolv quality in a smallest form factor possible, or are looking for Evolv quality at a lower pricepoint. If you dont have any of those requirements then build another DNA 200, its a better board for an advanced vapist.