In short: A concrete bucket is a smooth, toothless, tightly sealed bucket built for mixing and precisely pouring concrete. A regular digging bucket is designed for digging and loading soil, not for holding and directing wet material.

How does a concrete bucket differ?

A regular digging bucket often has teeth and a coarser edge suited to penetrating soil. A concrete bucket, by contrast, is smooth and sealed - the lack of teeth and gaps means concrete doesn't get stuck inside or leak out in the wrong spot.

The concrete bucket's edge is also often shaped so concrete can be poured from it in a controlled, precise way, for example into a foundation form or a tight space.

When is a concrete bucket the right choice?

Mixing and transporting concrete on site: mixing smaller volumes and carrying them to the pour location, where hiring a separate concrete mixer isn't worthwhile.
Precise pouring: foundations, post footings and other spots where concrete needs to go exactly where intended.
Handling concrete demolition debris: removing wet and dry concrete waste, where the seal prevents leakage.

When is a regular digging bucket enough?

If you're digging or loading dry material rather than handling wet concrete, the concrete bucket's special features aren't needed - a regular digging bucket is both cheaper and more versatile for everyday work.

What should you check when choosing?

Capacity: must match the typical volume of concrete you handle at once.
Material quality: the steel in contact with concrete must be wear-resistant, since concrete is abrasive.
Quick coupler: a concrete bucket is ordered to match your machine's quick coupler, just like other buckets.