Why the Two Names Persist Side by Side
Because they attract different people. "Colour prediction" sounds like a game and appeals to curiosity; "colour trading" sounds like finance and appeals to ambition; "big small" describes a bet and appeals to people who already know what they are doing. Same rounds, three audiences, and a marketing surface wide enough to reach all of them.
For a player, the practical consequence is that advice written under one label applies perfectly to the others. If you understand what a win pays and how many numbers your bet covers, you understand every version of this format regardless of what the buttons are coloured.
The One Genuine Difference
Bet variety. A colour build usually offers more ways to stake on the same draw — halves, colours, exact numbers, sometimes combinations — and more options mean more opportunities to pick a worse one. The simplest bet in the interface is almost always the one with the smallest edge, which is an unusual case of the boring choice also being the mathematically better one.
For the underlying round and its arithmetic, see the big small game guide. For why the charts and streak tools shipped with these builds cannot work, read the prediction and tricks page.