The key difference is that in prompt injection you'd be getting your jailbreak-prompt into someone else's model, for example, getting activated when their model

The key difference is that in prompt injection you'd be getting your jailbreak-prompt into someone else's model, for example, getting activated when their model reads your webpage or your email. Of course, it still does need to succeed in altering or bypassing your instruction prompt in any case, if it doesn't, that's not a working injection, so there are some grounds in treating it as related to jailbreaking.