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Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why is the 4.0 GPA scale used?

It seems like the 4.0 GPA scale isn't exactly reflective of a students academic ability. 
For example, let's say 90-100 = A+ = 4.0 and 85-89 = A = 3.9.
Student A gets 100 in 4 courses and 89 in 1 course, resulting in a GPA of 3.98.
Student B gets 90 in 5 courses, and ends up with a GPA of 4.0.
I don't know about you, but to me Student A has a better academic achievement than Student B, but their GPAs say otherwise. So why is this scale used?
gpt
>For example, let's say 90-100 = A+ = 4.0 and 85-89 = A = 3.9.

I've never seen that scale before.  I've always seen something more like:

97-100 = A+ = 4.33  
94-96 = A = 4.0  
90-93 = A- =  3.67  
87-89 = B+ = 3.33  
etc.  

Thus Student A has a GPA of 4.08, and Student B has a GPA of 3.67.