Sequential menu is when a user can only see sub-categories of the last category one has chosen. To get back to the list of categories one must push "Back" button.
If a menu hierarchy has 1-2 levels, a cost of interaction is relatively low.
1. Users can ocasionally mistake by pushing "back" button in a browser instead of the one on a website. As a result a user`s stay on a website can be over or one`s path can be interrupted. This is very bad for a user experience. To minimize this pitfall you can get rid of the "back" button and use trail of breadcrumbs instead.
2. If a user gets directly to some sub-category of a website, especially if a menu in this sub-category isn't long, one can not realize where one is and how to get to other main categories. As a result, a user may leave a website thinking that it doesn't work correctly.
3. Too complicated hierarchy and a long way to a needed page.
To sum up, we wouldn't advice you to use this type of menu on your website. You should better look at what Impressive Site menu has to offer: full customization, beautiful presets – all for your Wix site to look great!