Container block is universal block for all possible scenarios. It has wide settings for design and many extra options.
Here are some possible usages for Container block.
Css grid Container
Use all benefits from modern CSS grid structure. You can easily add non destructive grid of equal height columns, easily change place, merge columns and rows, add row and column gaps, duplicate columns, delete or add them.
Design options for other blocks
You can use Container block as wrapper for other blocks including core blocks. Just select any core block of WordPress, click to convert to container and it will be wrapped by Container block with all extra special design options
Flexible Container for inner elements
You can turn your container to Flexible block with wide range of options to align inner blocks with each other