Yes. If you care about your GPA or your class rank, then it does matter. Most colleges do not award A+'s, but they do award B+'s, C+'s and D+'s. And "usually" unless a college inflates their grading system, if they are on a 4.0 scale an A is a 4.0. And an A- would be a 3.7. So if you care about that, then yea, I guess it does matter. Especially if you want to later apply to grad school or something.
I don't know where the other posters went to school, but my transcript listed the letter grade for each particular class (e.g. A, B-, etc.) but for the GPA total for the semester, it had an average, like 3.3 or something. And many colleges have minimum cumulative GPA requirements to stay enrolled there or to graduate. For example, most schools will kick you out or put you on academic probation if your cumulative GPA is lower than a 2.0, which is a "C" average.
And your "class percentage" would matter to help the professor decide if you deserve an "A-" versus an "A" which could be the difference between your semester GPA and your cumulative being calculated using a 3.7 or a 4.0. So although they may only award you with a letter grade only, they have to have legitimate basis on how to award those letter grades, and then a numerical GPA number is given depending on the grade. In law school they don't give you letters at all. Like you would just get a grade for that class that says, "3.4" and you would just have to know that is in a "B+" range.
EDIT: It appears that many of the other posters do not, or did not attend colleges with "weighted grades" but it is more the norm to have weighted grades, so you need to look at the particular college's student handbook to know for certain.