The reason they're getting these is their previous ships fell apart from age.
They have a lot of coastline, a lot of fisheries to protect, huge amounts of commerce passing through.
What they're getting are nice ships, but pretty standard for what world navies are buying now; they're no superships or anything, and irrelevant to the US Navy.
They also have most of the natural resources, and the ability to use them, in the southern hemisphere.
They may not be relevant to the U.S. Navy but in the region they will become quite a formidable fleet & force projection platform.