
Standard laptop cases are generally styled like backpacks or briefcases. They usually have straps that sling over one or both shoulders, and they can carry other accessories, as well. They are meant for transporting and protecting a laptop.
A laptop sleeve case isn’t meant for transporting the laptop as much as it is for protecting it. Sleeves are generally meant to keep the computer from being scratched, dented, or cracked. They’re usually padded, and protect the computer against damage.
Some sleeves do come with shoulder straps, but most aren’t meant for transporting. Sleeves are generally used as extra protection for a computer inside a standard laptop case. Since many laptop cases don’t have a lot of extra padding, these sleeves can offer some additional buffer against bumps. They also help prevent scratches and dings in the computer itself that may be caused by other items inside the case bumping against the computer.