Light weights are they beneficial?
Offcourse its beneficial vs doin nothing. You wont get the results as when you would be able to go full out. Specially strenght and power wise. But putting ur muscle under tension and letting them work will give results ofc. It will just be a little harder to work your main muscle groups. But i think you should be glad with everything you can do and go with some try and error till you found ur limitations and try to do the best with what you can with them.
Whatever you can manage will always be a good thing. Dont think of any exercise as "womans" or "mans" think of it as doing everything you are able to do to the level which you can do it at. Just because its where you start doesnt mean its where youll stay. Ive always focused on light/more reps and body weight lifting personally and surprise plenty of people with the strength i have gained from just that