The following result is obtained by our expert's opinion:
People visit the travelling website for a purpose.
3D websites are used just to attract people who are very unaware about your business concepts or when you are having a very unique business concept then 3D websites will help you to attract new users.
The main reasons why travelling websites are not designed in 3D is because travelling website is already filled with very heavy media files like pictures and videos to make people have a look at the experience, which result in very slow loading speed of the website, then making it 3D will make it further slow. As people visit the travelling website for a purpose, they will get irritated more quickly due to slow load-up.