If you have done a great job or have great skills, it's one thing for you to tell others, but it's even better to have other people confirm this to others! QR allows you to gain endorsements and recommendations for your skills from members of the public that will be displayed on your public profile. This can be anything. From a client saying what a great service you've provided or an ex-colleague confirming you're the "go-to" person when when it comes to advice in your specialist are. Whatever it is, endorsements for your skills look great on your public profile. Even better a link to your profile can be included on CV's so potential employers and colleagues can see these endorsements. It's a powerful promotion and self-marketing tool.
The key is you often have to have to ask for endorsements! So what are you waiting for?
Also don't be sparing with your own praise, if a colleague, fellow professional or anyone else deserves an endorsements, let them know!