(FWIW I've got AmigaForever+Amikit for my pi400 just for fun, even though I've never actually owned an Amiga)

I assume that people who buy this browser this have either a PowerPC accelerator or run it under emulation? Can be used to browse (with limitations) to view modern websites?

It's hard to make a modern comparison. You simply can't visit most of the web because javascript doesn't work. This limits you to the handful of sites that are configured for amigas to visit. Those usually use very small pages with very lightweight use of HTML and few assets. so there's usually not too much to decrypt and pages load in ok time.

Timing Feels a lot like trying to use the web over 3G with first gen,2008 era smart phones. Though with many fewer sites to visit.

It's not so bad. It takes less than a minute to connect to most sites on a 25 MHz m68030 Amiga 3000.

Back in the day it was "best practices" to serve images on a website over http, not https, because decrypting an image-sized binary could take minutes on a 68030.