If by 'radio' you mean 'streamcast receiver' then yes, I guess.
Thus the interface of “changing channels” by rapidly pushing buttons is not so pleasing for a streaming-based player as it is for the real thing which is why Netflix provides the search and browsing interface it has.
Only for tuned stations. If you’re scanning the frequency (which is what the up and down arrow remind me more of) then it will take as long as it takes for your tuner to find the next station along. And that’s assuming you even have an automatic tuner, my first radio could only be manually tuned and didn’t support presets.
Real TV is all mpeg transport streams these days. Maybr you can tune in milliseconds, but you can't decode until you get a keyframe.
I always found a modicum of latency to be generally acceptable in something like TV tuning once it went digital. Streaming doesn't really offer anything with that kind of experience anymore. Even analog car radios tend to have digital tuners with their own degrees of tuning delay.
Can't remember where I saw this pointed out, but this Gibson quote from neuromancer won't make any sense to anyone young enough to have not been exposed to analog TV. And most radios by default do channel scan, so you aren't even exposed to audio static as much anymore either.
On the technical side, there is actually a way to make it to instantly switch (also fairly easy to implement) but it will consume more data (about 5x-10x) which would not go well with the efficiency of using a spare device concept. I had to consider these matters.