Think of it like this...a photon is both a wave, and the smallest discrete unit of energy

When the wave is absorbed by something, the energy must be transferred. But the smallest unit of energy is the full photon, and so the full amount of energy of the wave is absorbed at a single point, because there's no such thing as partial photons

Or in other words, the wave doesn't turn into a particle, the energy gets spent at a single point in space

Really, I think all of quantum physics works like this. Electrons don't exist as a point in space, they exist in an area. They're fields, they're not necessarily moving fast, which is why atoms don't randomly slip through each other and we can't measure all the properties of it at once