I'm currently doing this. I got everything I actually wanted from GNW treasure (Edo Sasori to 4*, Kushimaru and Jinpachi), so now I'm only drawing from Edo treasure for the extra Gengetsu frags I can get (along with getting them from the Exchange section). It'll take a while though but if you don't actually need anything else, I'd say go for it.

Wait for other people's opinions though.

You can try take a look at what BT are coming up soon.

Currently now, most of the EDO ninjas BT are coming out soon.

From there you can make your decision to draw them or not. GNW or EDO treasures.

In terms of long run, these draw treasure ninjas usually not fully used in LU or team battles but mostly for solo play.

Such as arena, or the Infinite challenges. Example, Temari GNW is one of the best ninja for Mystery Infinite.

She is a good ninja to invest in if you dont mind, she is also good for the upcoming Standard Atk Infinite.

I agree with the above poster, it is still worth it to draw in the GNW treasure because ninjas in that treasure are now getting BTs that are quite good. The most recent one (still only in China right now) is Edo Zabuza, but Edo Sasori is another example. I wouldn't be surprised if Edo Kushimaru and the other Mist Swordsmen got BT in the future. Fuguki also has BT out in China right now, they're not meta but they at least look fun (who knows when/if we will get this though lol, they've been out for like a year).

On the other hand, Edo Treasure has Gengetsu and Sage Kabuto (he just got good BT in CN). They are good with BT but two things to keep in mind:

First, it sounds like you are a fairly new player and it is going to take you AGES to get Gengetsu 4* and fully BT. For reference, I've been playing for 2 years and I don't even have him 4 starred (I could have if I had focused on getting his frags earlier, but I wasn't expecting him to get BT). His frags are ridiculously expensive in the exchange shop and because he comes by default as a 2 star ninja you get a low amount of frags every time you draw him in treasure, too.

Second, Kabuto is available through the exchange shop for survival trial points, but the Edo Swordsmen (except Zabuza) are only available there with Sun scrolls, and it would be...incredibly unwise, to put it nicely, to spend Sun scrolls on them. If the rest of them DO get bt, you are really stuck on options for getting them beyond treasure drawing.

Ultimately it's up to you if you want to hedge your bets on the rest of the Edo Swordsmen getting good BT or if you want to go for Gengetsu and Kabuto who are a safe bet in terms of BT but will take you probably like a year to get.