Site name in Title or not?

Hi

I noticed that on certain tools it defaults to putting '%sitename%' at the end of your page title.

However, when looking at some competitors, some did this and others didn't.

Is there any value to this or are you better using those characters for something else?

In case it matters, my domain name has my main two keywords in it (totalling 9 characters with the '.com' after that - so 13 in total).

Thanks