I chose the Zodiac and the N-Gage because they were two devices that tried to combine two different core functions.
Look at it, though - you still can't make a phone call with a Nintendo Switch. Phones have become gaming devices because they fundamentally represent ubiquitous computing. Once you're carrying around a CPU, someone will monetize every.single.aspect of that CPU.
From a hardware aspect, the n-gage was basically the Danger Hiptop but with a shitty keyboard. Yeah, the Hiptop wasn't considered a gaming platform... but the n-gage didn't have any games either so that's not really an advantage.