The point of a twin engine helo driver doing full touchdown autos is so that in the very unlikely event of having to do one for real, it will be survivable - in this case a decent simulator is fine for teaching it.
In the case of a single engine helo driver - in theory at least - the likelihood of having to do an EOL is increased; practice in a real aircraft is probably more desirable. It could be argued either way but somewhere along the line you have to retain an experience base of EOL skill and technique, even if it is only in your instructor cadre, so a basic SE trainer still makes sense.
A single engine trainer at least lets ALL pilots experience a real EOL in their training such that whatever they fly, they will have a pretty good idea of what to do and when.
The problem is in identifying a robust SE trainer that the manufacturers agree can be used as such - rather than procuring an aircraft that is then severely limited because what it actually needs to be used for doesn't match the manufacturers or contractors planned fatigue vs cost planning - and/or the contract is poorly worded.