Should a Roth Conversion e.g. $50k be exactly the same impact to this years taxes as a $50k wage income with no withholding?

I'd rather see it added as simple interest, or miscellaneous other income.  Showing it as wages will cause Turbotax to complain about the missing social security and medicare withholding.  I don't think it should have other effects but maybe it does.

Remember that to avoid an underpayment penalty, you must make an estimated payment by January 15, 2025, and then use the penalty form under "other tax situations" to calculate your penalty using the "annualized income method".  

The IRS assumes that income is earned evenly over the year and they want their tax payments the same way.  Assuming your tax is about $11,000, the IRS is going to want to see quarterly estimated payments of $2750 in April 2024, June, and September, in addition to January 2025.  By including the penalty form using the annualized income method, you show the IRS that some of your income was a lump sum, not spread out, and that your payments and withholding were correct when viewed on a quarter by quarter basis.  Otherwise, the IRS will likely assess an underpayment penalty for amounts not paid in April, June and September. 

By entering it as Wages may have qualified it for some credits.  You would have to print or look at the 1040 with the wages and then again with the ROTH and see what lines changed.  

There can be side-effects resulting from changes to the amount of wages that would not be present with a similar change in the amount of a Roth conversion and vice versa.  You'll need to compare the two Forms 1040 side by side to find out why the result is not the same.