I would prefer to phrase that dynamic as, no one would knowingly opt into a money that can do that to them, so these kinds of schemes require first lulling/lock

I would prefer to phrase that dynamic as, no one would knowingly opt into a money that can do that to them, so these kinds of schemes require first lulling/locking a population into that currency on a different promise, and only then debasing it, which is argued to solve certain public goods problems related to economies. That is, people only accepted dollars in the understanding that convertibility wouldn't be suspended, just like they accepted the historical money that Freicoin was modeled after before knowing they'd do the Silvio Gesell scheme. It's an open question whether we've accurately modeled the full knock-on effects of reneging on the promise that got the currency off the ground (though personally I agree with you).