Is it because when we have a bear market like now, people turn to bitcoin because it is more secure?
A good point. Alts are drastically decreasing it's respective price so at least for a
"safe" zone, others transfer funds at bitcoin for the moment until crypto market will regain it's dominance.
I think the opposite happened with the bull market last december, people turned to fancy alts because they thought they could hit the next 10× or 100×.
Back in that wonderful year, it's a wise move to take advantage of high bitcoin price by purchasing other altcoins. Since price movements of some alts are also having a crazy pump, it's way more preferred by others as they can good amount of bitcoin in return withing just a short period of time with the right strategy and trading execution.