It matters because pandoc is not rendering the website to pdf, it converts the html to latex and then uses a latex engine to render the pdf.

Forgive me but I don’t understand why that matters to you and am trying to understand what the issue with Latex is.

Because lots of things work this way. For example compilers built on LLV uses an intermediate language and Python uses byte code.

I suspect some html to pdf tools go through postScript.

There are multiple ways to "depend", so if pandoc executes some external tool all of the work then might as well use that external tool directly. You will get more control over how the conversion happens, know for what search for when in trouble etc.

My understanding and experience is that Latex has a significant learning curve and Pandoc provides a more gentle front end.

Of course Latex gives you fine control to hand tune the engine…but that doesn’t seem like what the OP is looking for.

Sure, I don't mean that anyone would look at the Latex in between. I'm just saying that if tool x directly calls tool y to do the job then might as well use tool y directly.

Since hammers and nails are a common tool-workpiece example…consider the nail gun.

Theoretically you can drive nails with a 22 caliber blank cartridge without making the “call” through a nail gun. But you won’t finish laying shingles as quickly and easily…

Or to put it another way, there’s a reason assemblers are almost always better than machine code and compilers are almost always better than assemblers for the ends people care about.

I mean why use Latex at all when you could write your own typesetting language? Maybe because you are not a knuth.