Explain what device emulators cannot catch

Task: Explain what testing in a browser's device emulator shows well and what only a real phone or tablet reveals. Context: I am a [your role] with [experience level] experience in testing. My site is [site description], and today I only test in the emulator of [browser name]. Rules: - Use plain words and define each technical term once. - Give exactly four things the emulator shows well and four things it can miss, with one concrete example from a site like mine for each miss. - You may be out of date on current emulator features, so end with a short list of claims I should check in the browser's own documentation. Result: Two bulleted lists of four items each, then a three-line rule of thumb for when to move from the emulator to a real device. At most 250 words.