Few reasons. First I might have read too much Anthony Bourdain when I first got into cooking. But after using one and not I have a few reasons.

Texture. If your making a smooth sauce thats gonna be Put the food processor or simmered into oblivion. It really doesn't matter what you do with the garlic. But for pasta And other dishes I prefer to have some sort of defined texture.

Flavor. It's probably the most intense garlic flavor you'll get from other methods of preparing garlic, which I guess is fine if you want hyper-intense garlic, but if you want something more mellow than using a garlic press isn't the way to go. Imo Microplains smashing it with a blade or hand chopping it,  helps you control the intensity of the garlic a little bit better.

I'm also a lazy bastard who hates cleaning the things and I also try not to keep too many one-use devices in my kitchen. Really, it does just come down to personal preferences. But I hate the fucking things. 😂