Sure, you could, absolutely. There are times when it is convenient to have one. For example, most fast food establishments will provide you a drink cup with a lid and straw. You could just rip the lid off and drink it normally, but if you are driving (which you probably are if you are getting fast food) and want a sip of your drink, it’s a lot easier to just grab the cup and take a sip through a straw than it is to grab the open container and tilt it. Not to mention the chance you might hit a bump or brake hard and have it spill, either while you are trying to drink from it or even just when it’s sitting in the cupholder if partially full.
Sure, you could, absolutely. There are times when it is convenient to have one. For example, most fast food establishments will provide you a drink cup with a lid and straw. You could just rip the lid off and drink it normally, but if you are driving (which you probably are if you are getting fast food) and want a sip of your drink, it’s a lot easier to just grab the cup and take a sip through a straw than it is to grab the open container and tilt it. Not to mention the chance you might hit a bump or brake hard and have it spill, either while you are trying to drink from it or even just when it’s sitting in the cupholder if partially full.