Search engine submission is not necessarily needed nor does it do any harm if it isn’t done. Various services that say they will submit your websites to different search engines is nothing more than getting the website crawled by those search engines. It is no different than creating a sitemap and submitting it to Google, Bing or Yahoo for better crawlability. What it comes down to is, yourpaying for a service that can be done on your own watch. Creating a sitemap is very easy to do, check out our guide for that. The sitemap just makes it much more easier for search engines to visit your site and scour your entire website without any bumps in the road, think hikers in the mountains. They have a map of the entire landscape to help them navigate much easier around the mountain than they would without it. The idea is the same with sitemaps and search engine crawlers, they work interchangeably.
Going back to the original question, is it necessary? No, it definitely is not. Submitting the website to the search engines just signals to them that your website is online & ready display on the web. Aside from using a sitemap to achieve the same net result, you can also create backlinks to your website in varieties of ways. Sending backlinks to your website gives the signal that your website is relevant to the site that is linking to you. Those search engine crawlers follow that link from the linking website and then begin to crawl your website as well. This in turn allows Google or any search engine for that matter to index your website to display it in their search results. Creating backlinks is a great way to get many of your deep pages on your website index much quicker compared to the very long delay it takes for Google to find it on their own.
If you find your newly created pages, post & even older ones are not index yet, be sure to check your sitemap, toss backlinks to it or submit it to indexers such as indexification or using tools like GSA indexer. Both options work very well and get pages index real quick.