You might be happy in your current job, but who knows the future these days? No harm in spreading your details - skills and contact details. And the best thing, when you offer your card to people, they invariably offer you theirs - a new future contact for if and when you need to move on.
And if you're currently job hunting, be prepared! Having a business card you can hand over is still the fastest way to pass your details face to face - and people don't refuse!