You pay tax on it eventually, like you said with the lower tax rate when your income will be presumably lower. But in the mean time, which can be a very long t

You pay tax on it eventually, like you said with the lower tax rate when your income will be presumably lower. But in the mean time, which can be a very long time, you're free to invest those deferred tax dollars. That can add up to a significant amount, over a large number of years. It's not something to trivially dismiss.