A dedicated macro ring/twin flash is helpful, but not essential for many macro shots.

If you already have an off-camera Speedlite, you can often get very good macro results by placing it close to the subject and diffusing it. In macro, even a normal flash can act like a relatively large, soft light source, so harsh shadows are often less of a problem than expected. It’s worth experimenting with your current flash first.

Where a ring or twin macro flash really helps is at very short working distances. Because it mounts around the lens, it can illuminate subjects that are hard to light from the side or above with a regular flash. That makes it especially useful for insects, tiny objects, and other close subjects where lens-to-subject distance is tight.

A tripod is still useful for stationary subjects, but flash often gives more control: faster shutter speeds, more depth of field from stopping down, and less dependence on ambient light. For moving subjects, flash is often more useful than a tripod.

So: for stationary subjects on a tripod, your current off-camera Speedlite is usually enough. Consider a macro ring/twin flash mainly if your subjects are extremely close, hard to light, or you want a more convenient dedicated macro setup.