Seems to me that people who wish to leverage the Bitcoin blockchain for various pet data projects would/could/should just peg out to a dedicated sidechain.  Unlike in earlier days (back before the earth stopped cooling) such technologies have been developed, and are working pretty well as best I can see.

Seems to me that a dedicated  sidechain would be a better choice than the Bitcoin blockchain since it wouldn't be being spammed by BTC transactions and there is a lot of unrelated cruft which could be left behind.

At first blush, somehow 'needing' to crud up the BTC blockchain seems more like an attack than a legitimate solution to a real problem.  Where is my thinking wrong here?