Well it was based off a particular dialect of Malay, but it’s certainly not exactly the same as that dialect, nor the language spoken in Malaysia today. The Interslavic language in the OP is also based on existing languages. It was also implemented the same way you’d imagine a created language would be. A central authority came up with the language, told the people to learn it, and then a couple hundred million of them actually did.

I think it has a remarkable quality, in that the government told everybody to learn a new common language, and that that actually succeeded. That’s the part where created languages usually come to a grinding halt. Whether the language is “created enough” seems open to interpretation to me.