By default, AI writing skews formal. Left to its own devices, it will produce copy that sounds like it was written by a committee for a corporate website. That's not how effective sales communication sounds.
Prevent this by being explicit about tone in your prompt. Some options that work well in sales contexts:
You can also show by example: paste a piece of your own writing you're happy with and say "match this tone." This is often the fastest way to get AI writing that sounds like you.