Medicare Supplement plans, also known as Medigap plans, are designed to work alongside Original Medicare to help cover some of the out-of-pocket costs that Original Medicare doesn't cover. There are several reasons why someone may choose to buy a Medicare Supplement plan:

1. More comprehensive coverage: Medicare Supplement plans can help fill the gaps in Original Medicare coverage, such as deductibles, coinsurance, and copayments. This can provide more comprehensive coverage and help reduce out-of-pocket costs.

2. Choice of healthcare providers: With a Medicare Supplement plan, you can typically see any healthcare provider who accepts Medicare, giving you more flexibility and control over your healthcare options.

3. No network restrictions: Unlike Medicare Advantage plans, which may have network restrictions, Medicare Supplement plans generally do not have network restrictions.

4. Guaranteed renewable: Medicare Supplement plans are guaranteed renewable, meaning that the insurance company cannot cancel your policy as long as you pay your premiums on time.

5. Predictable costs: With a Medicare Supplement plan, your costs are typically more predictable than they are with Original Medicare alone, making it easier to budget for healthcare expenses.

It's important to note that Medicare Supplement plans do not provide prescription drug coverage. If you want prescription drug coverage, you will need to enroll in a separate Medicare Part D plan. Additionally, Medicare Supplement plans can be more expensive than Medicare Advantage plans, so it's important to compare the costs and benefits of each type of plan before making a decision.