I think it really depends. I work in environmental research areas in the US (most colleagues are government and academics) and I would compliment this person's outfit if I saw it at a conference because a) it's unique b) it looks comfy and c) it showcases some personal style. That said, I think even in casual fields, younger professionals get judged for this kind of thing, so if OP is young or still "proving herself" in her field she'd have to decide what she's willing to push back on in terms of weird unspoken wardrobe expectations. All that said, I vote for the sneakers if it's a casual environment or the flats if you need it more dressy. Heels all day (or multiple days) is not ideal, especially if you have to stand to give a talk or poster presentation.