I'd push back a bit on framing this as an either/or thing - the real variable that matters more is how consistently you actually use whichever one you pick. That said, there's something to the writing-by-hand argument that goes beyond just "it feels more effortful."
When you're physically writing flashcards, you're forced to distill information into your own words on the spot, which means you catch gaps in your understanding right then. You can't just copy-paste a definition and fool yourself into thinking you know it. With Quizlet, it's way easier to passively scroll through someone else's deck or your own without really engaging. The flip side is that Quizlet has spaced repetition algorithms built in, so the app keeps showing you the cards you struggle with more often - that's genuinely useful and hard to replicate with a stack of paper cards.
If you're short on time before your midterm, honestly just go with whichever one keeps you studying without overthinking it. But if you've got a bit of runway, the hybrid approach makes sense: spend an hour writing out the cards yourself for the material you're shakiest on (that forces real thinking), then throw everything into Quizlet for the final week of review sessions. That way you get both the benefit of the creation process and the efficiency of algorithmic drilling right before test day.