You save money and lower your interest rate. This loan has minimal paperwork, lower closing costs, and a simpler approval process. Many VA homeowners find it easier to refinance at a lower rate and a cheaper monthly payment. And consider the VA funding fee, which costs 0.5% of the loan amount for a VA Streamline refinance, although your mortgage lender may allow you to include all of these costs in your loan balance.
You won't need to apply for a Certificate of Eligibility (COE), since a lender already confirmed your eligibility for the VA when you obtained your first mortgage for the VA. For example, if you currently have an FHA loan or a conventional loan but are eligible for the VA, you can use VA cash out refinance to refinance a VA mortgage with or without cash repayment at closing. If you don't have a lot of equity in your home, a VA IRRRL is probably more realistic than a conventional or cash-out refinance. Second mortgages on VA loans aren't common.
VA loans don't require a down payment, so there isn't enough home security to get a second mortgage. If you've already made six consecutive monthly payments on your current VA loan, you can probably refinance with an IRRRL.