"Better" could be numerous things.

Heat-resistance is one factor I've noticed between cements versus vulcanizing fluid. If you do fast downhills on rough tarmac with maximum-braking going into the corners, you may heat up the rims to the point where rubber-cement softens. The squirm of the tyres on the rough surface and under braking can work loose a patch that's using cement (gee, wonder how I now that).

Durability of the patch is variable as well. If you leave the tube in the tyre until it wear out, you probably won't ever notice the difference. However, if you're someone who changes tyres often, man-handling the cemented patch may work it loose. The ultimate comparison is to peel off a cemented patch versus a vulcanized one. While not representative of actual use, this worse-case-scenario will have the cemented patch coming off cleanly. The vulcanized one will require considerably more force and end up ripping and/or taking parts of the tube withit.

So basically, if cement is good enough for you, that's fine. For some people, the higher performance and durability may be factors that affects their usage.