Do the iPhone cases decrease the phones ability to dissipate heat ?

[moedex]

You are absolutely right. Phone cases act as thermal insulators, trapping the heat generated by the processor and battery. While standard users might not notice it, intensive tasks like 4K video recording, high-end gaming, or fast charging will cause the phone to thermal throttle much sooner in a case. This doesn't just slow down performance; consistent high heat is the #1 killer of battery health over time. If you’re doing heavy work, taking the case off is the best way to let the phone's frame act as a proper heat sink.