Good for anything?
It's good for burning your precious coins!
Will wallets accept it?
They should not since the address (the data part) is short and non-standard (20 byte instead of expected 32).
Will nodes propagate a transaction to it over the BTC network?
No because their IsStandardTx[1] check will recognize[2] such transactions as non-standard so they'll not propagate it.
[1]
https://github.com/bitcoin/bitcoin/blob/dfc35c99340da3236e2841b348580f0e881762ce/src/policy/policy.cpp#L94[2]
https://github.com/bitcoin/bitcoin/blob/dfc35c99340da3236e2841b348580f0e881762ce/src/script/solver.cpp#L164Can we use normal privkeys to spend from it with, as we do with regular native segwit?
I have to double check this but technically anybody should be able to spend any coins sent to such output. The reason is that witness program of any size other than 32 is valid but not-defined (also non-standard hence the burned coins as I said at first) so the node ignores verification of it expecting it to be a future change/soft-fork.
Due to lack of better terminology, we can call them P2WPKH(Bech32m). A thing or not? That's the question.
No because there is nothing like it defined in the consensus rules so the protocol sees it as an arbitrary hash not pubkey hash.