As opposed to the current system, where people without much money can't risk suing a company with deep pockets because they don't have the money for a lawyer.
If you have a solid case any good lawyer will take the case for a share of what you win - they won't win all such cases, but they have enough confidence in winning most that they can afford to accept a cases will be done without getting paid. However if there is loser pays lawyers cannot do this unless they either take a much larger share for the winnings (thus making it not worth anyone's time) so they can cover the lawyer fees when they lose a case they thought was obvious, or they need to warn potential clients there is risk they have to pay a lot of money on a loss.
Either way loser pays makes it more risky for a poor person to sue.
Money obviously is a factor in any case. But, if you hire a lawyer, you at least have control of the costs. "Loser pays" means you pay for the company's Big Law outside counsel if you lose.
Either way loser pays makes it more risky for a poor person to sue.