How much easier is it to decipher the pitches using something like this?Try using this for Chatter.
For that matter, are deciphering Chatter pitches only really useful in 4th gen for keeping track of frame advancements in D/P/Pt, or possibly for verifying seeds in areas with NPCs in those games? Without NPCs, it seems like verifying your seed with the Coin Flip app would be easier (and even if there are NPCs, unless your target frame is very low, you can use Chatter pitches to keep track of the frames that they advanced while you flipped the coins, which you can keep to a minimum by repeatedly opening and closing the menu during flips), and in HG/SS, you can verify your seed easily with the PokéGear (with no chance for NPCs to move in the process), and can also use it to keep track of frame advancements.