Taking this site as an example, “home working” is a pretty important keyword. I’d love it if I could be at the top of Google for that phrase. However, despite pouring heart, soul and a great many man-hours into creating a useful resource for home workers, I’m not yet anywhere near the first page of Google’s search results. (I’m actually languishing depressingly on the 11th page of results at the time of writing!)
It's wonderful to deal with keywords that have 5,000 searches a day, or even 500 searches a day, but in reality, these popular search terms actually make up less than 30% of the searches performed on the web. The remaining 70% lie in what's called the "long tail" of search. The long tail contains hundreds of millions of unique searches that might be conducted a few times in any given day, but, when taken together, comprise the majority of the world's search volume.
The limit on manual keywords could be higher. I personally wish we could input 10,000 keywords at a time, instead of 200. However, I understand the costs that Long Tail Pro has to maintain each time a new manual keyword is input. Not a deal breaker, I just wish the limit was higher. (To be fair, I don't think most keyword tools have a bulk manual option at all).