Maps + GPS are a great example, but generally any usage through which the phone gives you access to information in the right context (as opposed ti having to look up everything asynchronously from a computer) is invaluable. Being able to read email on the go to find an info (address, meeting time, previous interaction with someone, that time XX mentioned YY in an email, etc.), to check reviews on the quality purchases from the store (e.g. am I buying the right book books), to adapt and find a kid's playground/restaurant/transportation when travelling after having deviated from plans, etc.
It seems to me there is little debate in the fundamental benefits smartphones bring to the table, and what we need to work on is our relationship to the phone: querying it for info when we need it, and not letting it push useless info to us, as well put by the parent comment. Also, under that premise, any sort of entertainment should be avoided (it's just screentime with all it's negatives). Not sure how I'd classify Hacker News :)