While a job might not produce anything of value to a customer, I think it is often forgotten that a job also has the dual purpose of skills training.

People doing "useless" jobs might acquire the skills to do other and more useful jobs in the future. Keeping people unemployed has a high cost in the form of loss of skills over time, mental health etc.

If you don't keep things going you might risk losing some people forever as their skills become so obsolete and their motivation and work capacity destroyed.

Companies will usually not higher long term unemployed so that is why many people can get permanently lost to the labour market.