If you are riding for long periods of time then an insulated bottle won’t do much late in the ride. Even so, there's very little downside to insulated bottles. They may warm up before being empty but at least for a while, you'll get to enjoy the cool water.
Insulated water bottles contain an internal lining that helps to keep your water at the same temperature for longer. There's nothing worse than taking a mouthful of warm water when you're craving something cold and refreshing. The design of insulated bottles helps prevent that from happening.
However, they can be overkill if you're just going on a short ride on a comfortably temperate day. While there's not a lot of downsides to insulated options, the insulation reduces the water volume they can hold and they cost a bit more for the same function. When deciding whether or not they're worth it, think about how long you tend to ride for, and whether your local climate is likely to badly affect the temperature of your water.