Flash can be very time consuming. Some of the software is really expensive and confusing. If a web site is mostly all flash then search engines will have difficulties indexing pages. Try to add regular text along with flash so search engines can read pages better.
Flash have only designing but no concern with the Seo of the site which is the most important of all so thats why i think as a businessman we need the site designing that not effect the Seo of the site