I also live in Brooklyn (no doorman) and pay $9/mo for a USPS registered mailbox at a laundry store so that I never have to deal with the physical post office. I used to go there to pick up packages and it was a hellish experience. $9/mo saves all of that hassle and it is definitely worth it.
No, Amazon Lockers are nowhere near me (Williamsburg). I just don't see how it would be possible for them to scale as large as "neighborhood mailboxes" which are literally everywhere. There are at least 3 cheap mailbox / package drops on Bedford Ave on the walk home from the L train so I never have to go out of my way.