Winter weather at the seaside is unpredictable; it might still be snowing down below while the mountains are bathed in sunshine. Therefore, it's best to choose a good day for your trip, especially if you plan to see the night view, as visibility needs to be excellent.
The biggest characteristic of Japanese tourist attractions is their excellent management; they are generally well-organized.
Furthermore, the facilities are great. There are plenty of rest areas while enjoying the scenery, and the prices for food and drinks are similar to those outside.
With reasonable ticket prices, it's definitely worth a visit to Otaru.