What problem does this address?

The Query Loop block is arguably one of the most advanced blocks out there, and its complexity can intimidate and cause frustration to less advanced users.

What is your proposed solution?

Once #37080 is in place, the Query Loop block should be hidden from the inserter unless advanced users specifically search for it. This way, less advanced users will get exposed to the Query Loop block only through patterns and its block variations, such as Posts List, but the block will still be available for power users.