For a cryptocurrency, the cons of diminishing block subsidies (as required by a capped supply) are

1) concentration of wealth on early adopters

2) no long term security unless you have a constant backlog of high-fee paying transactions

I think an uncapped, disinflationary emission is to be preferred [1].

[1] https://john-tromp.medium.com/a-case-for-using-soft-total-su...