I think it is not possible for me to count and play at the same time, what is the actual goal of counting and playing at the same time?
The goal of counting and playing simoultaneously is (paradoxically) not to have to count at all when you play.
Nonetheless to approach that goal without learning to count first, will take you at least 5 times more time than if you are familiar with counting and playing.
There are three relationships we have with the metronome:
1) Metronome is our enemy (when we can’t play comfortably with it, keeps chasing us, or when it proves its superiority in speed, in other words when we feel helpless in his presence for any reason).
2) Metronome is our friend (when we can play easily with it, we feel happy playing along with it, and we even like his presence, as a friend it helps us to be accurate and to be near perfection in our performance, not to mention its paramount role in measuring and upgrading our technique etc.)
3) Metronome becomes our servant (this happens when we don’t need it anymore, because we have mastered rhythm and, even if it is there for example as a click in a recording session, we can literally play with the metronome instead of the metronome playing with us as in relationship n.1)
Therefore in stages 1 and 2 counting is a success factor. If you can count while playing a certain passage or phrase it means you mastered it. An example is here http://www.cfgstudio.com/cfgs-grant9.html
The counting is just externalizing our inner beat (and matching it with the metronome which is the objective point of reference) when you play something well you are already counting mentally or unconsciously, otherwise the melody or whatever you are playing will not be there properly.
Rhythm can always be improved through proper exercises and supervision.
So it is not a waste of time to try to master meter, rather one is wasting time by not doing it.
In my experience students that are familiar with counting and playing repeat far less times the passages or phrases or exercises to be able to play correctly than the ones who are not familiar with counting and playing simultaneously.
So it will save you much time and effort. There is the wrong assumption that counting while playing is difficult but the truth is that what is really difficult is not to count.
Counting helps you to understand the phrases as well as to internalize the rhythm.
Try to practice counting and playing 10 minutes a day and you will succeed!