The word "modularization" sounds pretty high-end, but honestly for ordinary people it might just mean two things: one is experiencing less lag and not having fees that scare you; two is that applications can iterate faster, so today on this chain, tomorrow switching to a different "base" might go unnoticed.

The ideal is beautiful: separating consensus, security, and execution, each doing their own thing, ultimately making wallets and apps as smooth as internet products.
But I also have a bit of cynicism... You think you're using "some chain," but in reality you're mostly using a set of front-end + a bunch of bridges and service providers, and when something goes wrong, everything blows up together. Recently, on-chain data tools and tagging systems have been criticized for lagging or misleading, which is quite fitting: with more modules, more middle layers, the narrative is easier to tell, and the truth is easier to package.
Anyway, I don’t pretend to understand everything; I just hold BTC for simplicity, and watch others avoid getting into trouble.