Quick link chain .. very very noddy question

[drivin_me_nuts]

Hi, super noddy question here.

I'm running 11 speed d12 and planning to replace one of the links on my chain with one of these

http://www.wiggle.co.uk/kmc-11-speed-chain-links/

I thought these were designed to be tool free and hence I was a little bit puzzled as to why the image says opening tool required. Err. what tool and if you need a tool what's the benefit of a quick link over just a chain tool and carrying a few spare links on you.

Also, whilst i'm here on this subject, are these any good or just smoke and mirrors?

http://www.wiggle.co.uk/shimano-hg70-116-link-11-s...

(on a Di2 Ultegra)

Regards,

confused of the sarf coast.