They impact some of the classes your child can take and the math track. If they are struggling get a tutor or work with them at home.

Remember your kid will also develop and grow and may care more when just a bit older. I noticed a big shift when puberty was full steam ahead. Executive functioning suddenly went from about 50% to 95% in my opinion. Everyone is different. She may be better able to understand consequences then too.

They only affect magnet admissions. If you don’t care about magnets, they really don’t matter.

My 10 year old is starting to get Bs sometimes but is a bright kid and I'm confident she would easily get As if she was motivated/cared about school and grades, but she very much isn't. This is sometimes due to mistakes/carelessness, and sometimes due to not paying enough attention in class and then not being motivated to get help to understand what she missed (ie she doesn't understand something on her math homework but isn't willing to accept a parental explanation and instead just guesses and moves on.)

Two questions:
1) Do grades actually affect anything kids care about in elementary or middle school? I'm guessing not, but if they do it would be helpful to lay that out for her and help her see that missing pieces of the foundation now might lead to lower grades later on which would cause X consequence she wouldn't like.
2) Do her grades affect anything *I* should care about, even if she doesn't? I guess they might keep her out of the middle school magnet lotteries (her test scores should qualify her for one or both) but I doubt she'd want to go anyway. Anything else?