You said that before me. So lets do the math now.
Moonlight Slash = 110 + Giant Water Shuriken = 170.
To deal with Fighting Fury Belt you then retreat and Giant Water Shuriken a second time, then attack.
(80 for attack) + (60 For each Giant Water Shuriken) + (30 from tool) = 230
In the current meta, the only thing that could survive, and in return 1 shot Greninja BREAK is a rogue M Gyarados.
I love how delicious those numbers are, especially since it's pretty dang easy to loop GWS over and over. Love it~
Not really that worried it has to deal with either Garbotoxin or the new and even faster Devour Light. Still nice to have a damage tool option for evolution Pokemon again. I don't know if EXes are going to jump straight on this card since most are basic and would rather have a little extra bulk with Fighting Fury Belt. They might slide in a copy om though for the KO chances perhaps.
I just like making puns is all. Because "sink" in? Hehe...heh...heh.
In all seriousness, I have a feeling Choice Band will play a larger factor in decks/strategies that can set up a good Stage 1 or Basic Pokemon (non-EX) that can scale well. Things like Vespiquen may enjoy this since she scales very well and 30 Damage helps her a LOT. Other things that come to mind are Raichu XY, who hits 190 off Sky Field + Full Bench (granted, Parallel City absolutely shreds the deck, but still), Flareon PLF (though, Muscle Band may simply be better), and Zoroark BREAK (specifically Zoroark BKT). Still, that seems to be the best kind of place to play this card.
Also, in regards to EX Pokemon, I don't see why they would give up FFB, no. What will probably happen is Choice Band will be played alongside FFB as kind of a utility-based thing. Actually... speaking of that, this would make Weavile STS extremely good in certain situations (Zygarde-EX immediately came to mind, now able to juggle 4 different tools instead of three).
This may come to that they also want Expanded being a bigger thing and in a way it's refreshing to see them considering previous eras for the game rather then looking forward and never back.
I have a feeling this is something we should be discussing as a general. With all the EX reprints (via boxes and most likely more Tins), I have a feeling they're going to continuously push Expanded as hard as they possibly can.
Either way, I really do love this card. It gives us another tool to play with when it comes to the numbers game and that always has been a big interest of mine.
-Asmer