The base rate
When the US government pays 5% a year to borrow for ten years, any other investment has to offer a reason to choose it over that safe 5%. That is why the 10-year yield acts as a base rate for the whole market.
Growth stocks feel it first
A company valued on profits far in the future is worth less today when yields are high, because those future profits are discounted at a higher rate. That is why the Nasdaq often falls when yields jump, even with no change in the companies themselves.
Gold and bitcoin pay nothing
Neither gold nor bitcoin pays interest. When safe yields are high, the cost of holding them rises. This is the main reason both can fall when the Fed is in a hiking cycle, even during frightening news.
Read the reason, not just the level
Yields rise for different reasons. Strong growth, rising inflation and heavy government borrowing all push them up, and each has a different meaning for stocks. Falling yields during a selloff usually mean money is hiding in Treasuries.
Cause Files on yields always try to name which of these is at work.