@Camillastore: Yes. Five reasons why...
1. Being a part of this "moving world". Achieving social influence represents a deep understanding of the nuances and mechanics of the world we live in today, namely one which blurs the line between online and offline. We are fast moving into a place where the relationships we nurture and protect in the digital world are as important and "real" as the ones in the physical world. Just as it is great to be around people who are socially comfortable, so it goes for people who behave engagingly online.
2. Thought leadership. Today, it's easy to share your passion with world - from a simple online portfolio, to a Vimeo channel, to blogging. It's when others pick up on that work and share it with their networks, that influence starts to be generated. It opens doors to other thought leaders in the same sphere and ignites conversation and debate. @millsustwo uses the word "prosper" - financial prosperity may be a by-product of influence, but social influencers prosper mainly through exchange of information and a strong eco-system.
3. Recruitment gold dust. It's exciting to find people who are both passionate about what they do and are great at it. For an employer, social influence is like a whole stack of letters of recommendation. If the people of the Internets are prepared to give the candidate their eyeballs and attention, then so might a client. For any employer, it's reassuring to know they're adding clout to their team and, if they play their cards right, potentially gain exposure to a new network themselves.
4. Going to market. Perhaps where influence as a key asset is most critical is for anyone working to bring a brand, product, service or personality to market. I'm so bored of hearing how "it's important to engage customers online", it's not "important", it's even beyond critical. It's pretty much the norm. That's not to say that it's the only way to reach your audience, the traditional components of the marketing mix are still powerful and relevant. But any brand working without "socially networked" people will be missing conversations, threats and opportunities.
5. SO hot right now. Overall, I think it's worth remembering that "social is so hot right now". Social and Apps - that's all anyone wants to talk about. Insinuate you've got a bit of social influence and they're throwing iPad 2s at you like there's no tomorrow. But there is a tomorrow and eventually everyone and every brand will feel a lot more comfortable operating in the social space. Social influence will still be a key asset, but in the same way being a "Team Player" or "Proficient in Microsoft Office" is today. It will be expected, a given. That said, the cream always rises to the top and the real influencers online will become ever more powerful, constantly turning the tide in 140 characters or less.