Not strictly, but they can be handy. Seatback and personal screens emit blue light like any device, and on long flights, especially overnight or across time zones, blocking that light in your destination's evening hours can help you sleep and ease jet lag. That's the main reason to pack them.
For daytime flying or short hops, they're optional, comfort more than necessity. If you're chasing better sleep on a red-eye or fighting jet lag, an amber lens (plus an eye mask and the cabin's dimmed lights) is a nice travel tool.
