In a way, the grinder serves as a test of willpower and discipline and those who could persevere through it can say they have the mental fortitude to handle stress and still achieve results despite adverse circumstances. Whenever I am kinda stressed out, I recall my time in school and it gives me something similar to "I have been through worse, I can make this work".
On the other hand, I tell everyone who bothers to ask that no, a PhD is not worth it. Get a master and go to work. Or better, get a BS and make the company sponsor that master degree. That PhD will drain both your life and energy and once you got it, you will still need to compete against people of your level. Nothing changes except a permanent mental scar.