There seems to be some misunderstanding about what checks are, because this is absolutely not a matter of the government "not accepting legal tender". Checks are not issued by the government, nor are they backed by a guarantee of cash. They are issued by private companies, and are merely backed by a private company's promise of cash.

And sure: it feels ridiculous that checks aren't accepted, but the reason they're not accepted is because they're not legal tender. Nor are they even cash-equivalent. They're only cash-equivalent by the (sure, contractually regulated but still entirely the) grace of the private issuer, and only for as long as that private issuer remains in business.