Go through the revision and bug history to see a sample of issues you're avoiding by using a highly-trafficked, well-supported solution.
The only reason not to use it is when they say they don't support a given feature that you need; and the nice thing there is that they'll usually say it, and have a good reason why.
The other reason to use pandoc is that while you might currently want PDF as your outbound format, you might end up preferring some other format (structured logically instead of by layout); with pandoc that change would be easy.
Finally, pandoc is extensible. If you do find that you want different output in some respect, you can easily write an plugin (in python or haskel or ...) to make exactly the tweak you need.
I mean everything has dependencies (some of the solutions elsewhere require Chrome and other common solutions require the JVM). At least Pandoc is GPL.
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.
Of course Latex gives you fine control to hand tune the engine…but that doesn’t seem like what the OP is looking for.