Grip importance increases the more arm- or shoulder injuries you had
This one should be self-explanatory too!
The more injuries you had, the more likely it is that your joints are injury-prone in general. The more severe these injuries were, the more careful you have to be while working out and thus also while choosing your grip position. If you are injured at the moment, chances are you can only use a few, certain grip angles in order to workout pain-free. In this case, it can be advisable to continue working out in these few angles to maintain your muscle mass. At the same time, though, you should obviously tackle the main problem together with a physiotherapist or similar.