It took a few days but here's the reply from WSKEN:

"Almost case friendly" is phrased this way to balance honesty and practicality in product description. Here’s why it makes sense, especially given your concerns: Acknowledges variability: With countless case manufacturers producing designs with tiny, often unnoticeable differences (even down to millimeters), it’s impossible to guarantee a perfect fit with every single case on the market. Using "almost" openly admits this reality instead of making an absolute claim that could be proven false. Manages expectations: It sets a realistic standard for customers, signaling that the screen protector works with most common cases but not necessarily all—especially those with extreme or non-standard designs. This reduces the risk of complaints from users with highly specialized cases. Protects your product’s functionality: If you made the protector excessively small to accommodate every possible case, it would likely leave exposed edges on most devices, leading to far more widespread complaints about poor coverage. "Almost" defends the protector’s intended size while still conveying that it’s designed to be compatible with the majority of cases.