"A powerful spec sheet for a low price, but key performance and efficiency metrics are conspicuously absent."
The '15,000 BTU' is a raw lab measurement; in your home, its real-world cooling for an 800 sq. ft. space will be challenged by the inherent inefficiencies of a single-hose portable design.
This is for a buyer who needs to cool a medium-to-large room on a strict budget and is willing to accept high energy costs and gamble on an unknown brand for a high power-to-price ratio on paper.
Anyone sensitive to noise or electricity costs should pass. If you need to reliably cool a room over 600 sq. ft., look for a dual-hose model or a window unit from a brand that publishes its SACC and CEER ratings.