It nullifies their powers, but to what degree? That's the confusing part. All we know is that it "emits the same properties/energy as the sea" (Smoker/Coby), it saps strength from the user (Enel), it nullifies Devil Fruit powers (Nami), and that it is made of (or contains) the same substance ('Plybotoin') that Sea/Land Clouds* are made of (Pagaya). The confusion is the parallel with the 'sea' or 'water'. When Luffy was under water (Arlong Park), his body retained its rubber properties, but lacked the strength and control over it. Luffy was also weakened and couldn't use his power when he fell into the Sea Cloud. So technically the Sea Cloud works the same as regular Sea, and does so because it is made of the same stuff as Seastone. Thus a confusing parellel. If he was pressed with seastone, would he then lose his ability to stretch entirely? It would appear so, from the evidence, but there has been no real verbal suggestion that Seastone has different (or more potent) effects on DF users.
Things can be made from the same source yet end up with different properties. Seastone can be tampered with so the effects aren't always as severe. Like the handcuffs which nullify the Devil Fruit ability yet the Power User isn't weakened at all.
Besides, we don't need to be outright told that there's a difference in effect between seastone and being submerged in water since we've seen just that many times in the story.
Right. So do you agree with my conclusion on that then?
Not really, since becoming a splitman gave Buggy an outright immunity to anything with an edge and as long as Ambition cannot cancel out Devil Fruit powers then that immunity stays.
Like let's say Ener was able to utlize Ambition and hit Luffy with an El Thor. I honestly think the attack would be ineffective even then since Ambition doesn't cancel out a Power User who's body was permanently altered(logias and become/control paramecias). So Luffy's state as a rubberman(and immunity to electricity) would still be there.