It really depends on your prompt and the text you're doing.
But for Medea, structural devices (and Greek metalanguage) are an integral part of the text. As you are analysing an Ancient Greek play many of the structural and historical contexts of the piece are different if you compare it to the modern era, with actual Athenian male audiences, (the only input for them is verbal language/structural devices) mentioning and analysing your text through structural devices can be very helpful in enhancing the quality of your essays.
If you're doing a film in your comparative the importance of visual analyses is self-explanatory, and for texts like "Tracks", it's useful and better to compare the structural devices used between both texts.
Lacking these devices/metalanguage wouldn't necessarily hurt your mark in any way, but if you acknowledge and analyse the structural aspect of your text your chances of scoring high will be much higher (just a personal opinion)