They're just another tourist attraction. Honestly, we don't find them that interesting. You can't go inside. A handful of them might get occasionally opened up for visitors maybe one day every five years or so. Some of them have nice grounds where you can have a picnic, look at the water, and take a picture of the lighthouse, all enjoyable ways to spend a summer afternoon. Others are at the end of breakwaters that you can walk out on. If it's a foggy day, you might hear a foghorn. That's about all the nuance I have to offer.

There isn't anything special about them we could tell you that you can't just google for yourself. There used to be lighthouse fan organizations, kind of like antique auto clubs so that might be a place to start. If you search this sub, you'll find nice pictures other people have taken of them.

If you take some time to get an idea of what area you want to visit or which lighthouses look interesting to you, and you still have questions about them, maybe try again. Specific questions get better answers than general ones. Maybe pick two you like the looks of and ask which is better to visit with little kids for example.

If I asked /georgia what's the deal with the peaches, I wouldn't expect to get much useful info.