Keyword Planner can do all of these things except:
suggest keywords and ad groups that may not have occurred to you
multiply keyword lists together
provide Quality Score estimates and validate keywords
provide historical statistics on search volume
Explanation:
Keyword Planner is a free AdWords tool for new or experienced advertisers that’s like a workshop for building new Search Network campaigns or expanding existing ones. You can search for keyword and ad group ideas, see how a list of keywords might perform, and even create a new keyword list by multiplying several lists of keywords together. Keyword Planner can also help you choose competitive bids and budgets to use with your campaigns.
Read more here: https://support.google.com/adwords/answer/2999770