A recharacterization transfer provides a bonus. And a recharacterization can come to your rescue if you roll a regular IRA to a Roth IRA and later find that you don't qualify for that rollover. If you make a recharacterization you're treated as if you rolled the money to a regular IRA, which is a tax-free transaction. If your excess contribution to the Roth IRA would also be an excess contribution in a regular IRA you can't use this method to avoid a penalty. For example, if you waited more than 60 days to complete a rollover, you won't be able to fix the problem by making a recharacterization.
Full details concerning recharacterization transfers appear in the following pages.