I proposed this idea a while back, caling it “Grin vouchers”. You can find the reasoning and use cases here. Yes, it can be used if someone specifically wants 2 steps but it is by no means ment to replace normal three step transactions.
I see its use mostly for air-drop, vouchers, top-up cards etc. I do think “the Grin vouchers” idea has merrits as a “add on” to normal grin.
I think mimble-wimble.py would be a great place to develop and test ‘fun-features’ such as grin vouchers. I can totally see myself transfer funds from my normal wallet to a less secure python wallet, where I create temp wallets/vouchers to sell or give away as air-drops. Since it is python, developing somethink like this can be done by me or others who can code but are not at the level of "core"developers.