Comment by zerocrates

Obviously it depends what you're working on, what your patterns are, and so on. But my experience is that PHP involves so much array wrangling that devs are more likely to have a handle on what an array will do in this context (an empty array is falsy).

It's the string ones (in particular that in addition to the empty string, "0" specifically is the only other falsy string) that tend to catch people out.