I did a mini LA/
Disneyland trip with DS 21 last January. I looked at options and ended up deciding to do the car rental route. We flew into LAX, stayed overnight near Hollywood, had one full packed day for LA things, and then spend three nights in Anaheim and went to Disneyland and California Adventure. I thought the car was the quickest way to do different things in LA -- We in a very busy full day did the Warner Brothers Studio tour, the Griffith Observatory, stopped at a Lolli and Pops flagship store at a big mall (DS works part time at one of these where we live), went to the Hollywood area to see the stars and the Madame Tussauds Wax Museum, headed to the Santa Monica pier, and then drove to Disneyland where we parked our car and kept it parked the whole time (heaven after dealing with LA traffic). The days at Disneyland and CA adventure were great, and then last day we drove back to LAX to fly home. Do note, though, too as I was checking out of our lodging place on our LA day, so I really and truly needed the car as a place for luggage storage. We used the WAZE app for getting around and dealing with traffic in LA, and that was a great app to have.
Yes -- we paid for parking while we were at our hotel -- I think $14 a night. You can ask and check out one way rentals, etc. With more limited hours for non-airport locations and sometimes one way rental charges, sometimes it's easier, more convenient, and cheaper to just keep the car, even if you aren't using it. I know with our limited time and busy plans, that would not have worked with our itinerary. If the hours work for you, though, and the rental location is really close and someone has an hour or so to kill and take care of that, why not. // Never hurts to look at options.