Hashtag Suggestions for Twitter

Today I had an idea, what if Twitter had some kind of hashtags suggestion on the compose screen?

My idea: when you want to write a tweet, at the bottom of the screen appear some popular hashtags that you may want to tweet about. When you tap on one of them (or start typing), the rest disappear and you can type whatever you want. The hashtag would always be displayed at the end of the tweet.

So, what do you think?