BNB and BCH are two different coins from different ecosystems, but their faithful time charts always show similar movements. If BNB is rising then BCH will be at a standstill or experiencing a small decline and if BCH is rising then BNB will be in the opposite condition.

Is it because the market conditions of BCH and BNB actually have the same fanatical community?

This is just a view, visibly not based on actual research. But just want to build an aegument from a thought based on momentary movements.

Indeed, BNB and BCH are at different levels and also very different circulation systems. But when viewed from the formation of the two coins as currencies, it seems that the market for both moves alternately between them. Not overlapping, just like a spinning wheel.

So if taken at a glance it means that if one of the coins has increased then one has decreased, so that the profit side can be taken for a moment even though it cannot be predicted in terms of its sustainability.

This is just an opinion or argument for a moment, the risk of hope is in your own hands. Do not be easily influenced by a writing, do good and correct research and decisions.