Converting PostScript to anything else is rather hard. To see why you should stop thinking of a PostScript file as a document but instead think of it as a programming language which is capable of giving a printing device instructions that will cause it to print out the document.

Yes, if you send a PostScript printer the correct document rather than printing it will instead install a stealth backdoor that contacts someone and tells them that their latest victim is waiting. I forget whether the default password on HP printers was "OOOO" or "OOOOOO", but it is fairly simple to guess. And, as you can imagine, most people don't realize that their printer is a fairly capable reprogrammable computer, with an operating system (written in PostScript), full networking capabilities, etc.