Your money would go in at 25% now if you're single. I anticipate that my money will be coming out in the marginal 28% bracket, married. So, there would be a small benefit there.
Also, the Roth grows tax free, so while I paid tax on the money I put in, I won't pay tax on the growth. The money you put in as a resident will have 30 years to grow before you retire, and 4o years before you have to take RMDs at age 70 1/2. By then, the money you put in as a resident will have multiplied to many times what you put in as a resident , but all of the growth will be tax free. Plus, you get flexibility because that money is not subject to Required Mandatory Distributions (RMD) withdrawals when you turn 70 1/2. It can be inherited by heirs income tax free ( but not estate tax free).
For most retired physicians, you will want to have both traditional and Roth IRAs. As a resident, you will be in a 25% bracket if single, so you pay the tax, and put the money in a Roth. You would benefit from contributing to a Roth for any bracket below your marginal tax rate, and it would be a wash for the same bracket. For example, my top bracket while working was 35%, and that money went into a traditional IRA. When I take it out, some of that money that I didn't pay 35% tax on, will be coming out of my IRA and filling up the lower tax brackets, so some of that money will pay 15% ( social security will fill the 10% bracket), some will pay 25%, and some 28%. So, it went in at a 35% savings, but now is being taxed at a lower rate.
Meanwhile, if I had no Roth, but more money in my traditional IRA, I would be forced to take out more money ( due to mandatory required minimum distributions RMD) and thus pay more at a higher bracket, and I might even hit the 35% bracket. However, by having money in the Roth, I decrease my RMDs, plus, if I need more money than the RMD requires, I can take it out from the Roth tax free, instead of taking it out of the traditional IRA at a higher tax rate.