They aren't heavy, but they are big/bulky. You can't just stuff them in a pocket. Ironically, the "bad" plastic bags (thicker and bigger than standard US grocery bags, but still a single layer of soft plastic film) could be folded into a pocket, while the new "reusable" ones can't, making it harder to actually reuse them.
This is incorrect. There are reusable bags that fold into pocket sized. Ikea has them, among other brands. Now that you know, I'm sure you'll reevaluate your outlook on them, right?
Additionally, if you're coming back from work, you probably already have a bag to carry stuff you need for work that you can use to carry a "spur of the moment" amount of groceries or other bags. However, this sounds more like a regular occurrence you are neglecting to prepare for rather than a spur of the moment thing.
This is incorrect. There are reusable bags that fold into pocket sized. Ikea has them, among other brands. Now that you know, I'm sure you'll reevaluate your outlook on them, right?
Additionally, if you're coming back from work, you probably already have a bag to carry stuff you need for work that you can use to carry a "spur of the moment" amount of groceries or other bags. However, this sounds more like a regular occurrence you are neglecting to prepare for rather than a spur of the moment thing.