A Private Pilot License (PPL) allows you to fly small aircraft privately. It lets you enjoy flying for leisure sightseeing or personal travel. It does not allow flying for pay or commercial airline work. Many people get PPL simply because they love flying. It gives you basic flying skills experience and the joy of being in control of an aircraft. PPL often becomes a first step if you later want to get a Commercial Pilot License (CPL).
Strictly speaking no you cannot earn a fixed salary or regular income just by holding PPL. Because PPL is meant for private flying regulators don't allow PPL holders to fly passengers or aircraft for money. That means you cannot join major airlines or get paid as a pilot with only PPL. For such jobs CPL (or further license upgrades) is mandatory.
However there are limited and uncommon situations like flying for small private charter services or flying clubs where PPL holders might get some paid flying but those are rare and often need additional certification or employer acceptance.
It gives you real experience and flying hours useful if you later upgrade to CPL.
It lets you fly privately for fun travel or hobby.
If you aim for a flying career starting from PPL and then going CPL / higher PPL is a good first step.