I have had boxes there for a while now and I think the model is genuinely good, with two caveats that people consistently discover in the wrong order. Taking the question seriously because it is the right question.
What the missing account actually costs you
It costs you recovery. That is the whole of it. There is no password reset, no billing history to point at, no support agent who can be persuaded that you are you, because from the provider's side there is no you — there is a token that paid for a server. If you lose the key material and the token, the box is not yours any more and there is no argument available. Everyone reads this as a privacy feature, which it is, and nobody reads it as an operational constraint, which it also is.
The corollary is that your backup story has to be complete before the first box goes live rather than after. Not "I have snapshots", which live in the same place as the thing you are backing up. Off-box, somewhere unrelated, tested by actually restoring once.
What it buys back
No email, no name, no account record to be handed to anybody. Five dollars for thirty days, paid in Monero, BCH or BTC. The CLI and API are the interface rather than a bolt-on, which means the entire lifecycle is scriptable — I rebuild rather than repair, and a box that is disposable by design is a box you never sit up at 3am nursing. That inverts the failure mode in the thread title. Nothing breaks at 3am because nothing is precious.
The caveat I would put in bold if I could
United States jurisdiction. This is not a bulletproof host and does not claim to be. The absence of an account limits what can be produced about you, but the infrastructure sits somewhere with a functioning and enthusiastic legal process, and a subpoena to the datacentre does not care that the customer record is empty. If your reason for wanting anonymous hosting is takedown resistance rather than data minimisation, this is the wrong tier and you want one of the offshore names instead.
So: for tooling, relays, scrapers, throwaway infrastructure and anything where the box is cattle — yes, and it is the cleanest thing in the category. For the estate that pays your rent, no.
Uncertainty
I have not run anything there needing more than a modest amount of memory, so I cannot speak to the larger sizes at all, and I have never had one expire on me because I overpay the clock deliberately. Ravenstack's question above is a real gap and I would not want to answer it from assumption.
Summary: disposable by design is a feature until you treat one of them as permanent, and the day you do is the day the model stops protecting you.