Capitalist firms are a somewhat stable forms of organization under capitalism. The average lifespan of a company in the S&P 500 was about 20 years (as of 2020). For small businesses, it is harder to find information, but one source gives an average lifespan of 8.5 years¹.

Cooperatives are even more stable:

For example, statistics from France showed a particularly high survival rate of conversions of conventional companies into worker cooperatives: there was a three-year survival rate of 80-90% for these cooperatives, converted from “in crisis” or “sound” enterprises, respectively. Compare this to a 66% three-year survival rate for all French enterprises. Likewise, the five-year survival rate of cooperatives formed from existing businesses was 61-82%; this figure for all French businesses was 50%.²

See the above reference for more evidence and theories on the increased resilience of cooperatives.

So cooperatives are a form of worker self-organization that lasts for a decently long time. They also have some more specific positive properties:

• They furnish worker-owners with a stable source of wages.
• They may accumulate productive equipment and real-estate.
• They may provide worker-owners with general leadership and communication skills

They have negative properties as well. Namely, they have some tendency (less than a conventional capitalist firm) to reproduce the negative external effects of capitalist organization, because they are subject to market pressures. I think this is overstated, as it only really becomes relevant at a scale much larger than what most businesses will achieve.