Do you mean the importance of mind control in poker? Well that is the most important thing, if there is no control your mind basically you can not play poker
Depends if you mean finding a stake from some people to play x amount of x game or backers that pay your bankroll to grind say sngs full time.
When I play staked by some guys off here it's purely for fun to get a rail going.
When I am being backed by an individual or 'staking company' it helps you deal with variance and as long as your ev is going up the backers will carry on sending the funds. Instead of down swinging and it costing you money which can affect your mental game for sure.