I find it generally easier to cut items into portion sizes before cooking them sous vide.
- It makes the size more manageable in your water bath.
- You don't have to worry as much about temperature ramp-up time between outer surface and core of food item.
- For delicate proteins, means there's less handling of the item post-cooking.
I completely agree, I'm just stating the alternative. Sometimes standard freezer ziploc bags aren't even big enough. I was doing a large prime rib a while ago and has to use the larger size freezer bags that aren't normally available at my grocery store. If you used something else you would need a large amount of butter/liquid to get rid of the air.