TBCOnet – first off Google AdWords Keyword Tool gives viable options to bid on. I really only use the numbers as directional – espcially for SEO.
Online Casino returns 1.5 million searches globally. So I am not sure if you read the info incorrectly or you are simply getting different results.
Keyword research tools you should use:
KeywordDiscovery.com
AdWords Keyword Suggestion tool
WordStream – The Free Keyword Tool from WordStream – Free Keywords for SEO, AdWords, & Blogging
Now with any tool you need to really understand they are not 100% accurate, but they will give you directional data regardless.
Good Luck with “Online Casino” – those sites are dug in like ticks