They are not familiar with power law and Bitcoin data in particular (unless you mean Sina and for sure I can have a discussion with him about this). 

Invite the professor in a space and we can discuss.

Anyway, if you start with the statement: create a regression (that in this case means a linear regression) using Quantile regression, of the log of the price and the log of time you are creating a power law model. 

No professor will disagree with me on this.