Most classes already in place are "Theory"-based and not practical in the least so in turn it comes to rise that P.E. Being the outlier actually makes no sense. It is completely impractical to force people to exercise for an hour a day without them knowing why they are or what the benefits of the behavior actually is.
Phy Ed is not about homework or theories of sports. It is about learning how to play various sports, and most importantly of all, having a lot of fun while learning something new in the process. PE is not about unecssary homework and work sheets that are a waste of time.
P.E is about helping students get the exercise needed to stay healthy. If you take that time away, what is the point of the subject? There's no need to teach people, in PE, what happens to the body when you exercise; this is because most people, if not everyone, understands that staying fit and healthy is a good thing. Therefore, give students the exercise they need.
I personally do not believe this is a good move. P.E should be about physical literacy - skills, fitness, tactical understanding, etc. Not how many facts a child can cram in before an exam (which is unfortunately how many other subjects have ended up). P.E assessment should be 50% theory at most.