There are a few reasons for this:
Sometimes plugin updates are released with bugs. Updating less frequently allows the plugin developer to get rid of these bugs before we add them to your WordPress site.
Batching more updates together means an easier manual review. That in turn means a lower probability that something bad will happen or break your website.
We’ll be doing all these updates on the weekend when most websites receive less traffic. That means a safer environment and minimal issues for your visitors.
We always make an exception for more major plugin updates, such as WooCommerce. When major updates come out for this, we’ll make the updates far more slowly to ensure that your website remains running smoothly without any hiccups.