28 minutes ago, Laurentius said:I think they'd be great for milkshakes and smoothies, too.
They are not: they are essntially tiny filtration devices designed to separate solids from a low viscosity liquid (yerba mate / tea laves, and in its non-sanctioned rogue usage for bubble tea / tapioca pearls). If you like to drink a smooth, high viscosity liquid you'll be looking for a large diameter straw that doesn't add addtional pressure loss to your slurping process by an additional filter.