I personally think a lot of this stuff resembles vegan "meat" products, which always seemed silly to me. If one is ideologically opposed to Hitler, it would be weird to make a point of styling your mustache like him and dressing up like him on the weekends as a means of embracing that opposition. Likewise, if one is ideologically opposed to meat products, it's an odd behavior to seek out products that attempt to physically resemble them and obsess over finding ones that are the closest in appearance and taste to the real thing.

I get that vegan's justify this by arguing that they desire meat, but without the suffering and some conclude this is a sort of least bad compromise so no need to explain that to me. I'm just illustrating the appearance of absurdity to someone who isn't a vegan.
Further, such "fake" products are generally going to be nutritionally inferior to the real thing because they need to contain a witch's brew of ingredients and processing aids to properly simulate the taste, color, and mouthfeel. Generally those aren't selected for nutritional value, but for those specific qualities and may or may not be things a person would wish to put in their mouths from a nutrition optimization perspective.
So with functional cooking, I find myself wondering what I'm really trying to accomplish when I engage in it, beyond possibly enjoying the creativity aspect of it. Sure, I might be able to make cupcakes with a lower net-carb count and glycemic index than "normal" cupcakes, but am I not just reinforcing an addiction behavior that causes me to seek out cupcakes that are less bad (in terms of glycemic index perhaps), but that likely contains other ingredients that are highly processed and nutritionally ambiguous (VS eating whole foods)? And hey, if I'm taking a GLP I could probably handle the occasional real cupcake mixed in with a more whole-foods focused diet VS going through all this rigamarole?
To be clear, I'm not casting judgement on anybody else who enjoys functional cooking as a hobby or saying that's how anybody else should think about it. I'm just sharing the internal mental process that I went through when pondering why I was doing what I was doing that way and where it led me.