When I first started my company my financial advisor suggested this dude... look at these rates!..
No wonder there is a huge market for it

At a fundamental level psychologists and psychotherapists (well good ones) are knowledgeable friends. They are people that have got the compassion and patience to properly spend the time help someone work through their problems and achieve what makes them happy in life. On a practice level all the knowledge about brains and minds are directed towards promoting this wellbeing in their clients.
Lots of people that for whatever reason do not have these support structures in life may well find that the company that comes with some life coach blowing smoke up their arse is all they need to get out their and tidy their bedroom. There are certainly elements of life coaching that are going to be interventional or even inspirational. Rarely in my experience is it based on any evidence base (though important to remember one of the biggest predictors of successful interventions is therapeutic relationships) and usually these are narcissistic people that are doing this kind of work for the wrong reasons.