Doesn't the different distribution shapes of the respective variables (e.g., binary vs. fractional) influence the regression coefficients per se?
As the binary variable represents only "extreme values" of the fractional variable, 0 or 1.
Example:
dependent variable: payment yes/no 0,1
independent variable a): gender male/female 0,1
ind. var. b): percentage of items in the basket that are green [0,1]
=> IV a) can only have 2 values 0 or 1, whereas IV b) can have infinite values between 0 and 1