Flash navigation on sites

Often heard that a flash is bad. And flash navigation all the more. Why bad?
Those who say so say that flash navigation is poorly handled by search engines, if a flash is not installed, then the user, in principle, is deprived of the opportunity to work with the site.

The aforementioned problems can be easily solved by using SWFObject.

The idea is that flash navigation replaces a block with a regular non-flash menu.
If the flash is installed, then the user sees the flash version of the navigation , and if the flash is not installed, then the usual navigation .