The coil spares patients from surgery. There is no cutting. Recuperation from the procedure is quick. Coil treatment should last forever. Not all brain aneurysms can be managed with the coil procedure.
Surgery is still the treatment of choice for many aneurysms.
I am a frequent Red Cross blood donor. I recently made my 100th donation. They usually use a vein in my left arm but often bump into scar tissue that plugs the needle. A vein scar bears no relation to a clot. Usually what occludes a needle is its position in the vein.