Why Twitter?

Yesterday I attended a seminar on social networking at Bradford Crafts Centre by Chi-Chi Ekweozor of RealFreshTV.
One of the social networks discussed was Twitter, which Chi-Chi favours above Facebook. Now I am a big fan of Facebook as a promotional tool for both Glassprimitif and for Keighley Arts Factory because, through my business page and group, I can target my audience locally. By local I mean increasing the foot fall to the gallery and also increase UK sales to my folksy shop. I am not as keen on Twitter because I wonder how it's possible to make those all important relationships on such a frenetic site?
Question: everyone is madly posting links (Buy my latest ..... See my blog..... Visit my shop.... ) but are we actually bothering to look at the links? I would have to spend ALL my time on Twitter to look at, and comment on, every link I am sent. Also, Twitter seems so "trivial" to me, does it really have a long shelf life as a promotional tool?
I think I need convincing - Chi-Chi was so enthusiastic about Twitter that she has made me think that Twitter may well be a valid marketing tool but the jury's still out in Primitif World!
If you have an opinion on Twitter please let me know.