Your potentional buyers and clients are on Linkedin. This is especially important if you are in B2B (business to business), if other firms are your clients.
Your colleagues who have Linkedin profile can edit firm they work for in their profile and you will get link to your company page automatically. Visibility will be bigger and their contacts will see every update from your company each time your worker interact with it.
Big plus is also for SEO optimization. Google like companies which are active on Linkedin and it sees firm as more serious if page is well and regularly maintained.