The dollar remains the easiest rosetta stone for figuring out what you've got, i.e., what your bitcoins and other assets are worth. It will continue to be easier to use a more stable currency for that purpose, unless something goes wrong with it.
People invested, in both the financial and emotional sense, tell others to hold because that drives the price up more. The subculture's vernacular even includes "HODL", a joking way to tell someone to keep doing their part to drive prices up.
It's painfully obvious what people are doing.