You can also filter by query, which is useful when looking at branded queries, or when looking at specific words. For example, only show keywords that include the term "SEO". The graph also allows you to spot trends in across the available metrics and compare week-on-week or month-on-month. This can help you to drill down and monitor progression over time, allowing you to answer questions like "have my branded keywords received more clicks in the last month compared to the previous month?", "has the CTR improved?", "did average positions in Google improve?".
In fact, Google Suggest is the best way to find good long tail keywords that people use to find information on Google. Google admits that while Google Autocomplete (another name for the Google Suggest feature) was not designed specifically for marketing, it can deliver meaningful insights and help stay on top of trends. There are also many clever ways to use Google Autocomplete that can help you with SEO.

Keyword Researcher is designed to search the Autocomplete databases of Google, YouTube, and even That's a lot of keyword sources! As you probably know, if you're building an authority site, or if you would like to become a dominant player in your niche, then starting with a large database of keywords (that your customers are actually typing in) is a powerful marketing tool.
As for the history of the company, as I explained, I created Long Tail Pro back in 2011.  At the time, I was creating tons of niche sites and was doing alot of keyword research and content creation.  I was trying to figure out what types of keywords would rank quickly in the search engines, specifically Google, and I was frustrated with the other keyword research tools (in particular Market Samurai) out there.