The fetch as Google tool tells you what Google sees when it spiders your site. It's useful for figuring out if you have some technical issue that's preventing the bot from crawling your site properly.

As far as I know, it will not help you with indexing or removing content.

Moreover, can i use the tool without "submit to index"? Because i can fetch as much as 500 urls per week but can only send to index only 10 urls per month.

You can fetch and then submit 500 urls to the index, the limit of 10 applies only to submitting a page and all the pages it directly links to. For example if you had a sitemap page with links to every page in your site, if you submitted that sitemap page, in essence you will have submitted your entire site.

I have changed titles on pages and seen the titles change in the SERPS in 10 minutes after a submission.

Hmm, that sounds interesting. How many page titles did you change bumpski? I have a big number of pages, that's why i ask you.

[webmasterworld.com...]

In the thread above I talked about Google's recent title length tweak. It seemed like about twenty titles were altered by Google to TWO word titles.
I'll give Google credit, I was able to tweak the title length slightly, to the point where Google would show the actual title, and was able to review the results in short order using "fetch as google" and then submitting the single URL's for the pages in question, and then quickly see the results in the SERPS with the desired titles.
I was astonished at first, but for some changes Google's index was updated rapidly. At times you might get an "everflux" effect where, things would revert to the way they were, but after a day or so everything seemed stable and the desired titles remained.

I was told that the fetch tool itself won't get Google to crawl the page sooner, but if you submit it to the index after fetching, that will speed things up.