Let's say I was in the market for buying a Cessna. What benefits would buying a new Cessna have over an older one? With cars, the resale value does hit a floor as long as it is safe to drive. Are planes the same? Is the fuel efficiency worth buying a new Cessna or is it more of a status thing?
Do planes depreciate like cars?
Planes do not really depreciate like cars per say but aircraft engines kind of do!
Planes are a bit different than cars due to the certification process being far more verbose. Year to year changes tend to be non-existent or come down to trim/paint options. As such a well maintained old aircraft with a fresh/low time engine may fetch more than a new aircraft with a run out engine.
There are also a lot more factors that go into the value of an aircraft even from airframe to airframe in the same make and model where cars can have some options the avionics combinations for most light aircraft are nearly endless.
Is the fuel efficiency worth buying a new Cessna or is it more of a status thing?
A brand new Cessna 172 is no more fuel efficient than a 172 from 30 years ago (more or less) because the design largely has not changed. Unlike cars that get small aerodynamic and engine changes often, it's far more complicated to change aircraft designs and deal with the certification so designs remain largely unchanged short of small and limited improvements.
I'm not really sure its a status thing, thats highly opinionated and a bit off topic here.