Is the Protestant Work Ethic Ethical?

Been thinking about Max Weber's work lately and in his book The Protestant Ethic and the Spirit of Capitalism, he considers the fact that Catholics at the time held significantly less power and wealth throughout Europe than their Protestant counterparts. One of the factors he examines is cultural difference in terms of attitudes towards work.

Is hard work intrinsically virtuous? There is no doubt that it can be taken to an extreme and, sure, that is problematic. But take two co-workers, one who takes initiative and plugs away and gets everything done as efficiently as possible, while the other does only what is asked and not a lick more and who takes his time getting done what he does. Or, alternatively, one student who studies hard, outlines the text, works sample problems and gets good grades while another with all the same aptitude, skates through with C's. We can call the one a better employee and one the better student, but is this a reflection of character, does this make either one a better person than their colleague? Is our inclination towards the hard worker something ingrained in us because of its benefits for the big boss man or is it an indication of something deeper?