I'd be surprised if anyone reads it. No disrespect. It's just I can't see anyone sitting down to read a personal letter and then the CV and then do that for all the candidates before even an interview. You'd be surprised what recruiters do in order to sift through their workload quickly.

Having said that write a short statement of who you are and why you feel the job is important to you. Make it... personal to you. Obviously. Can't hurt to have one even if they don't read it in full. I wouldn't spend a lot of time on it.

What's the points and the job?