6 months to break even... at fixed difficulty. Nah, thx. But 5/7 for effort.
The utility of these can't really be measure in months to ROI

They are designed for people that don't have the means, or can't have a huge loud hot miner in their room. Its a great way to get into mining, learn about crypto, and get your friends into mining and spear the word about Litecoin etc.
With that being said these are definitely the most profitable USB miners in recent memory. My original moonlander I think had a 10 month + ROI on launch, and the only other USB miner on the market is Sidehacks that does about $1 per month in BTC profit.