It takes two...
During classes, after the teacher has demonstrated the sequence, I envy the couples à la ville
who can immediately begin to rehearse, while I have to wait patiently until some follower becomes available. And when this happens, I still can't exercise immediately, we have to "adjust" for a while with simple steps until the connection is there, before embarking on the nice pattern (e.g. back saccada with double jump) which is the subject of the class.
I also envy them because they can practise, i.e. repeat indefinitely the same sequence until it works. This is something I theoretically could do too, if I happened to be in an empty milonga (you need space to practise) with a student follower, who would have assisted the same class, who would be available, (alone, not with friends or husband, not already invited by advanced dancers), willing to practise. In real life this never happens, of course. During the milongas all I can do is refine somehow the patterns I already know, mainly the 8CB. And most of the nice steps I'm taught are quickly forgotten.
So, the cons are obvious: the steps are more difficult to learn for me during the classes, and impossible to practise. The pros do exist, yet: the constant feeling of frustration for not having someone to dance with suits well with tango. Remember, this is "A sad feeling that can be danced", therefore at least I'm in the appropriate mood. Also, varying the partners avoids taking habits such as "half-leading" (I just lead the beginning of the pattern, the woman recognizes it and finishes it on her own), anticipation (the woman knows that after a giro I always lead a gancho) and so on.
So theoretically, in the long run it is probably a good thing. I will develop into a better leader, but it will take me 14 years instead of the 7 it usually needs. In real life, of course, I'll be dead by then.