Obviously Bitcoin price; the amount Bitcoin is worth at a particular time, and Bitcoin usage; the rate at which Bitcoin is adopted and used. The above phenoms surely has implications, one may be tempted to as; which is more important?
They both works together, as people have to adopt the use of bitcoin in other for them to increase the more with its acceptance level and this will helps it demands to increase at the same direction, while at the end, we acheive an increase in market price, because it's value increases over time and remains the most profitable crypto asset they can invest, so both depend on each other, while we needed more for adoption and demand to make it's value ever increasing being a volatile market.