No, that's not right at all. You would rather have your money compounding in a Roth where growth is tax free than growing in your tIRA where it's taxed. If you pay taxes out of the conversion, it's a tie, but if you pay taxes from your taxable account and have the entire converted amount going into the Roth, the earlier you convert the better.
This is all assuming is all in the same tax bracket. The standard rule applies that you are better off converting if your current tax rate is the same or lower than you expect it to be later when you have to take RMDs.
OK...I ran some numbers and you are correct in that it is a tie...assuming 8% growth for both accounts and the same tax bracket comparing early conversion versus later conversion. However, the words..."earlier you convert, the better" may not apply if it is a tie....when both will be Roth accounts having nearly the same value.
It appears it depends mostly on your tax bracket at the time of conversion and your tax bracket during retirement. I was a high earner during my working years in a very high tax bracket. After retirement, my tax bracket is less so a tIRA worked for me. The RMD did not affect me because I re-married a woman 20 years younger than me so my RMD is reduced because the age of your spouse is a factor in determining your RMD. My wife has a Roth IRA because her income is less than my income during my working years so in her case, a Roth IRA works better for her.