Nobie
Gordos are basically the main reason to use Dedede from a gameplay perspective. I believe his entire re-tooled kit from Brawl was based around their use, and is a big reason why he has a lot of the weaknesses he does.
When used properly, gordos force your opponent to commit to one of numerous options. This is great for Dedede (or any character, really): guess right, or if your opponent just messes up, and you get big reward. Consider this:
Dedede lobs an up-tilted gordo from about 1/3 the distance from the ledge to cover your getup options.
Cool, pressure's on you now. You have a variety of ways to handle this, but Dedede has a potential counter in place for all of them, and you don't want to get hit by him at all. You don't want to get hit by Gordo itself, either, for the same reasons. So what do you do?
- Wait on ledge. If the gordo wasn't spaced properly, it won't hit you. But now you have to get up without your invincibility, or he can set up the same trap if you wait too long. If it was spaced properly, gordo hits and stagespikes you from a hanging position. Ouch.
- Swat it away, either with getup attack or a rising aerial. He can either re-reflect it for absurd damage, or go for a shield grab. You don't want either of those.
- Neutral getup, shield gordo. Dedede gets a grab, you don't want this.
- Neutral getup, swat gordo. Same scenario as before.
- Jump+airdodge. This puts you closer to gordo's bounce, so mistiming means it hits you. With proper timing, if read, you eat a bair instead. Ouch.
- Roll getup. Negates gordo entirely, but if read, you eat a down smash. Ouch.
It's why Gordos are such a fascinating move, I think. The pressure exerted from them is immense, and creates this really intricate counter-counter design between you and D3. And that's not even talking about the way they travel, either, which in itself is complicated (dealing with arcing, bouncing projectiles that get affected by height, slope, etc. takes a lot of thought from both parties).
So what makes them considered somewhat underwhelming at times is that setting up these scenarios is either a rare opportunity or a complete gamble, because the act of tossing one out carries a very long commitment (FAF of 64, fastest possible attack after that is frame 6). Normally that wouldn't be such a big deal, but Gordos being Gordos, the risk of getting them reflected before you can even attempt to guess their action is a big one. And Dedede being Dedede, him getting the space and/or stage control needed to get set up is a daunting task.
Additionally,
by their very design, Gordos carry risks for Dedede even when he has the time to launch one safely. He basically has to predict your reaction by necessity, since he doesn't have the mobility nor the frame data to punish any of them by reaction alone. If he can't read you, you get out of pressure without much trouble.
Despite all of that, Gordos are good. Give them to any character with half-decent mobility and/or frame data and they'd be horrifying. It's a lingering, bouncing, living, 14% projectile with an absurd amount of variables that could change how it moves.