Great no one can alter my notes, but they can be suppressed by the relays or deleted altogether. I really have no guarantee that what I want to tell the world, can be seen by the world; I have to trust that some unknown operator(s) will be so kind to serve it.

If I want to make really sure stuff exists and is accessible to everyone (e.g. my blogs Git repos, Shopstr listings, etc), then I am back to self hosting.