The road to Pon Beach is blocked by a hotel, which will only let guests get access to the beach. Thus, to visit the beach, you have two options, you can stay at The Naka Phuket Villa, where prices start at about 20,000 baht per night for a villa, or you can arrive at the beach by sea.
The photo is from before they finished building the hotel. If you follow the link above, you will see that the hotel looks very different now.
Read more in the article Pon Beach.