Out of curiosity, which altcoins?
Can't recall the name.
What about the added requirement of a good CSPRNG source for every tx (not required by ECDSA), something which is more difficult to obtain in an isolated IoT environment w/o added (and unauditable) hardware support?
It's not needed, you already have a cryptographic hash function and publish SHA3(txData+secret) on the 1st step and reveal the secret on the 2nd when the network verifies that SHA3(secret) matches the spending address.
There's also extra non-volatile state which much be maintained to commit the tx, another weak suit of IoT devices in general, correct?
Probably, depends on an implementation.
ECDSA isn't that hard, otherwise hardware wallets wouldn't exist....
Can you imagine, IoT requires a more lightweight algorithms base.