Why not MSCI ACWI

Hey everyone, maybe a stupid question. I invest mainly in the iShares MSCI ACWI UCITS ETF (Acc) and wonder why the MSCI ACWI is comparatively rarely read about here. Mostly it is about the MSCI World, the FTSE All-World or a combination of MSCI World + Emerging Markets. Am I missing something? Does the FTSE All-World or the MSCI World + Emerging Markets combination have a real advantage over the MSCI ACWI - apart from the fact that the FTSE contains more companies