If reproductive labour is done then it has to be paid for somehow. If it is unpaid as you put it, it just means that the worker is paying for it themselves rather than it being paid for by the employer or social infrastructure. If it is unpaid in this sense then it effectively depresses wages, because a (significant) part of the wage is being spent on something that is a necessity in both individual and societal senses.

If you don’t have someone to watch your children for free, either your employer needs to pay you enough to afford a daycare or your survival depends on finding a job that does. Family planning benefits are one way that companies justify paying a lower wage and obfuscating that. They become golden handcuffs where they exist, entirely useless if you don’t want to have children and a necessity if you do.

If you don’t have someone to clean your house and feed you, you’d burn out working an exploitative job that doesn’t leave you with enough time to do either. That could be paid professional work with a maid and a restaurant, but the existence of the housewife means your boss doesn’t need to pay you enough to afford meeting your basic needs or give you enough time off to fulfill them. It means those jobs you’d otherwise rely on are more culturally/legally marginalised as feminised labour and devalued because someone is compelled to do that work for free.