Speaking of styles... Melanie Watt

Unless you yourself are afraid to leave your nut tree and explore the world, you probably know Scaredy Squirrel. I first read this several years ago and bought the book without blinking.
It popped into my head as I was thinking of a blog post for this week so I looked it up. The series is now up to 4 books, there is a puppet, and there is a TV show in the works. If that's not enough, it's also #46 on School Library Journal's top 100 picture books (a good list to browse anytime!) That's the type of success I know many of us would love to achieve, but here's where it gets really interesting for me.
I browsed this book she illustrated at our local garden store a few years ago. I was grabbed by the lovely cover, and surprised to see that it was illustrated by Melanie Watt. Such a different style from the flat, cartoonish Scaredy Squirrel. Gorgeous though, right?
And then there's this other style I saw. I haven't read this, but the cover is beautiful and so very different than the other two styles. Perhaps I'm looking for a little comfort since I'm experimenting with style currently too. Is this the type of thing that is allowed when you have a little (or a lot, in Melanie's case!) success under your belt? Is this something that is almost irrelevant when you're pitching your own dummy? So long as the style is appealing and suited to the story, are you free to play? Just thinking out loud here as I work on a new style and think of where it might take me.