Yes, some employers care about whether you were a good student or not. Your transcripts can be particularly important if you are applying to popular jobs -- for which there are many applicants for each available position.
Employers look at your grades to see if you have a history of doing a good job and being a "high-level performer." They are not looking to hire slackers and/or nurses who struggled to learn the material -- unless they have positions that are hard to fill because they are unpopular. The more desparate the employer is, the less they will care about your grades. If they have plenty of good applicants for their positions, they will become more demanding and raise their standards -- as you would expect.