What is Google Suggest? When you type first part or first word of a search term Google automatically suggest rest of your search terms as you typed based on the most popular searches.
How does Google Suggest help your Google search experience? Mainly it auto fills what you might be looking for. Google Suggest reduce the chance of spelling error. It helps you choose the most specific search terms. Google Suggest saves lot of your time.
How is Google Suggest different from Related Searches Queries? While Google Suggest is a group of auto filled term based on the first part or first word of your search term, related search queries are different. It shows the most relevant associated search terms based on the topic.
Small spelling error can show a confused search result. Very un-specific search terms can show non relevant search result. Typing in-complete terms can take long time to see what you want. But Google Suggest can solve all these problems. Try Google Suggest and it will bring positive result on your search experience.