Because it's actually easy and fast, and through hole rework is a pain.

I say this from the point of view of an electronics manufacturing tech, so YMMV.

Because the only reason you think through-hole is easier is that you're accustomed to it.

Starting from scratch, a syringe of paste and some tweezers is not only easier, it's faster and smaller. Young eyes might not even need a magnifying glass. There's no pile of sharp little trimmed leads everywhere afterward, even!

I teach newbies SMT all the time at my local makerspace. It's insanely easy.

Here's at least one very good reason: the 74LVC161284 buffer is only available as SMD. 0603 resistors and caps are pretty easy to solder by hand and you can buy convenient component boxes with a hundred different values that take up the space of a book.

Soldering the whole thing together took less than an hour. Having a microscope definitely helped.

There's nothing maddening in soldering 0804/0603 SMD if you have the right tools. With a good flux you can even do it with your eyes closed. Smaller sizes require at least a magnifying glass and a steady hand though.