Liquidity

To do this well requires sufficient risk absorbing capital.

Of course, but not if they make the whole system riskier. I dont know how to judge this at this level of generality.

The creation of credit-based money in this form facilitates payments, serving markets in a basic way that would be hard to replace.

depends on alternatives considered in the question.

Maturity transformation has its place; the devil is in the details.

I understand "liquid" here to mean safe more than low transaction cost.

Consumers want liquid and safe securities. Firms' assets are often illiquid. Both sides can benefit if firms issue shares and senior debt.

"Social value" is odd wording. However, such institutions are likely to make markets more efficient by relaxing undue liquidity constraints

That is why narrow banking is a mistake. If we ban this, it will move to the shadow banking system.
-see background information here
-see background information here

-see background information here

Such institutions can also impose social costs. If done well, the benefits outweigh the costs. The trick is to ensure this is the case.

Gains from trade. Yes, I am assuming such institutions are suitably regulated.

Captured very nicely by the Diamond-Dybvig (1983) model and others
-see background information here

Bills of exchange and other "liquid asset" go back many centuries.