Not all plans are available in every county. If you plan to live in another state or travel, the Uniform plan is the only option. Few if any rely on Medicare alone for coverage. The Health Care Authority plans are secondary to Medicare but pay for items that Medicare does not. This is availabe from the Health Care Authority as an option.
Some benefits are limited.
If you drop it, you can add it again at an open enrollment but must stay 2 years. May be important in some circumstances. You must pass health scrutiny, but it is not too difficult to get. Your employee insurance ends at retirement. Premiums are high for the conversion.