if/else coding style consequences

I am a novice programmer and was in lecture one evening, we were studying the "if,else" coding section from my professor and I was curious about an aspect of it. What I was curious about was if we have a bunch of nested if,else's in our program, is it just bad coding style to end an if,else with an "else,if" line of code instead of if "x", else "y"? For example,

if "x"
else if "y"
else if "z"
end

compared to

if "x"
else if "y"
else "z"
end

It would still run the program without an error, but are there consequences later on other than having bad programming style?