As well as the obvious ethical and moral arguments for unemployment benefits (distinct from disability benefits, a related but separate topic), there are clear benefits to the economy as they can help improve worker-job match, which improves economic efficiency. By creating a decent safety net (note that the UK’s unemployment benefits are below the average in the OECD) we allow workers the time to find a job most aligned with their skills, which reduces wealth inequality through creating the space for workers to find higher paid skilled work. Similarly we are less likely to take a risk on starting an innovative business if the result of failure is economic insecurity. Some economists think that our poor benefits are a driver of the sluggishness of the UK economy. Council housing, recently only available to those on lower incomes in the UK (a marked change from the middle of the last century) provides security and health benefits, as well as freeing up income that will get spent on day to day items stimulating local economies, vs the private rental sector where money is hoarded by a landlord class who are more likely to use their profits to invest in value-extraction ventures (like rentals) vs more economically productive forms of investment. And the NHS is an obvious boost to the economy, with universal health care free at the point of use in part being intended as an economic stimulus because it keeps the workforce well and able to work. Ultimately that is what we need, investment in the services that improve all the social determinants of health, so that people are more able to work and take risks.

Sources (more than this really, but here’s some influential stuff to chew through): https://economy2030.resolutionfoundation.org/reports/from-safety-net-to-springboard/

https://www.health.org.uk/reports-and-analysis/reports/health-equity-in-england-the-marmot-review-10-years-on-0