His main selling points are ease of upgrades/repairs as well as reduction in hazardous wastes. While I agree with Hakkens on ease of upgrade and repairs, yet it's not clear how throwing away old smartphone components whenever better ones are introduced can reduce hazardous waste.
The desktop PC was one of those successful but unruly implementations of modular electronics for a consumer product. Hakkens's idea will bring compactness and form to modular smartphones and possibly other consumer electronics.
I like modular designs. The idea oozes neatness. Squarish things that fit neatly together bring back warm LEGO memories. Snap out the old and snap in the new and you can custom-build a new phone altogether. Sounds like a winner to me, but it is not a green idea. If any, modular phones may generate more hazardous trash as more and more phone users purchase upgrades on a regular basis and throw away the old parts.
A complete functional phone, when discarded due to old age, for example, can still be recycled by other users. But what will happen to old discarded phone components such as an old GPS module or an old touchscreen? Will these components trickle down to other users with greater or less frequency than whole phones? Who knows.
I tend to keep my phones for about 3 years before I give them away. But let's assume for a moment that every 3 years or so my phones end at the top of the hazardous e-waste heap.
If I own a modular smartphone, I would most likely swap my old camera with a newer hi-res modular camera and throw away the old one. Weeks later, if a new GPS module comes along for my phone, my old GPS will get swapped out. My WiFi module too. Maybe when Bluetooth 5.0 comes out I will swap it with the old Bluetooth.
And since not many countries handle hazardous electronic waste disposal properly, my old camera, GPS, WiFi, and Bluetooth modules will find their way into municipal trash dumps. How is this any better than traditional phone designs as far as being environment-friendly? Is generating e-trash year-round better on the environment then let's say generating trash every 2-3 years when a phone is discarded?
In reality, being the pack rat that I am, no electronic part will be discarded but instead will find a home in an Arduino geeky project. But you see the picture. Millions of phone users swapping and discarding old smartphone modules with newer better ones. This can generate e-waste too.
So yes to modular smartphones because it's a neat and efficient idea but as long as we realize the cost to the environment is still unclear.
Modular smartphones should not be promoted as environmentally-friendly alternatives to traditional smartphone designs. They should be promoted as a smart, functional design.