The hardware is used to support the area while a fusion is getting underway. It can take up to a year for a good, strong fusion to grow, so the hardware is there to keep things from shifting in the meantime. It's really not an either/or type of thing. Occasionally, a doctor will do a fusion and not put in hardware, but usually they do. But I've never heard of putting hardware along the spine without doing a fusion.
It's a tough decision, but if you decide to go ahead with it, don't second guess yourself. Remind yourself of all the reasons you made the decision and just stick with it. If you really need the surgery, you'll be so glad to get it over with and be on the road to recovery!
If you have other questions, please ask. And you might want to read the sticky at the top called. "post surgery tips". It will give you an idea of what to expect after the procedure. I've had two fusions, 30 years apart, and both helped me tremendously. I'd make the same decisions again in a heartbeat if I had to go back and do it all over again.
Blessings,
Emily