Yes, there is a disadvantage to claiming that you are contributing your pension money to a Roth.
You are only allowed to contribute earned income to a retirement account. You may not contribute unearned income, such as from a pension.
As long as you have earned income, you may continue contributing to both your and your wife's IRAs, up to the contribution limit or the amount of your earned income, whichever is smaller. Once you stop working, you will no longer be able to contribute.
You can contribute to a traditional IRA if you are under age 70 1/2 or at any age for a Roth. Certain other limits apply.
