One of my friends had subscribed to LinkedIn premium. He tried to find jobs in Australia about 2 years ago. He couldn’t find any because LinkedIn premium had been serving him the freely available material like :
Looks like you are looking for a job.
In that case you will be able to contact people directly without a need to be connected, this might seem intrusive, but some recruiters would value your tenacity.
Also, when getting Premium, I noticed more recruiters reaching out to me. I would say it’s like a signal you give out to them.
As for your friend, looks like something is missing there. Why exactly wasn’t he able to find anything?