To those suggesting to inhume beggars, that is a very ill thought out recommendation.
The beggars are needed primarily in the Thieves Guild quests, and are criticaly essential in the Master Trainer Speechcraft pilgrimage. In the Speechcraft pilgrimage, ANY beggars killed before starting that pilgrimage will result in the pilgrimage being unable to ever be completed.
Jenifur Charne
Yes, but not all assassins are necessarily thieves. Plus, they kill for a living, I doubt they'd be masters of being able to socialize, don't you? I mean, killing isn't exactly the most popular profession. When's the last time you heard "Oh, check out that charming cute-hooded-killer-dude over in the corner of the Inn!" from a lady-friend while chilling out in town?
:P
That being said, you are right. Those looking to become master of speechcraft should avoid killing beggars. Same goes for those who wish to join the thieves guild in the future.