The simple answer is no - search engine submission isn’t necessary. The majority of search engines nowadays (most notably Google) crawl and index pages by following links. Using that logic, a single inbound link from any already-indexed page will identify your page to the engine. Subsequently, if that page links to other pages within your site, they will also be indexed… and so on.

SEO is not an exact science. This becomes apparent when trying to incorporate both SEO and branding into a strategy. This process is finicky to say the least. On the one side, SEO deals with the placement of keywords and phrases. On the other side, branding deals with company loyalty and culture. Incorporating both sides dilutes the prominence of both. But eliminating one or the other may not meet all strategic and marketing goals.