Help me out !

Hello dear experts;

A- " You did an excellent job explaining the good points of cell phones; they're convenient, we feel safer always being able to call someone, and they are very helpful in business."

1- Is " explaining the good points of cell phones" an object complement for the job and is that why it is used in gerund form?

2- being able...... Why is it in a gerund form? and what's its grammatical role?