Is there any reason to try to get A's in undergraduate courses once you are accepted into a PhD program?

[Segnaposto]

I was recently lucky enough to be accepted into a PhD program. All my courses for this undergraduate year were electives and have no baring on things that I would need to know for future graduate work. Is there any reason to continue trying to get A's in these courses or is it safe to relax a bit and study for prelims this fall? My advisor said he and many people he knew just stopped caring about the classes. His reasoning was that their undergrad GPA ultimately didn't matter once they got into a graduate program. Was curious is this was the case or if he was exaggerating. 

Edited April 6, 2019 by Segnaposto

[MarineBluePsy]

Your overall undergraduate GPA may impact funding opportunities early in your PhD program.  Some funding lines may expect a higher incoming GPA and you may not want to eliminate those opportunities by slacking off too much now.  

[PsyDuck90]

I don't think you necessarily have to get straight A's, but I wouldn't just start neglecting all the class responsibilities. Technically, I assume your offer is contingent on your performance and graduating GPA being appropriate. So like, if you get some B's is one thing, but if your last semester is all D's and F's, that may be an issue.