So, what problems does it solve? In this case, it gives the Z80 an amazing co-processor that will push the Z80 itself, into the stratosphere of modern connectivity.
The RP2350 can be used with older, 8-bit computers, to really open up the world to them.
It is the ultimate upgrade/accessory co-processor, for Z80, 6502, 68000-based retro- computing/alternative-platform based designs and so on..
Oh, for a retro-computing nerd, the RP2350 has solved so, so many problems!
The biggest bug-bear for retro computers is: storage (and also connectivity).
For example, in my retro collection I have machines where the RP2350 has given these 8-bit computers access to as much as 32 gigabytes of storage - and in many cases that is many, many, many times of a multiple too much space, even if you put everything that was ever written for the 8-bit computer, on the SD card.
However, if you have ever hacked on a retro computer, you will know that storage is everything, and having everything that was ever released/made available for any particular platform one might curate, is simply a delight.
The RP2350 has opened that vista wide.