Even if proposed for vicarious motives, the technology as such may still be the right way to go.
From an environmental perspective, CO2 sequestration for EOR (enhanced oil recovery) makes little sense, other than reducing the carbon footprint of production a bit, demonstrating the storage principle and further developing key technology.
What makes more sense is to use geological storage for CO2 captured from industrial processes other than power generation - production of cement, steel and chemicals, in other words processes that would release large amounts of CO2 even if switching 100% to renewable energy.
Also, we need some place to store all that CO2 that purportedly would be captured using DAC (direct air capture) in the future.
Sequestring CO2 is a huge scale problem, and all solutions have significant flaws. Forests require vasts amounts of land, and storage is only assured as long as nobody decides to chop down the forest for other more pressing purposes (looking at you, Brazil). Storing CO2 in oceans (either in the form of "ocean fertilization" or by directly dissolving CO2 in seawater) could have huge and unknown consequences for marine ecosystems. Other solutions such as biochar and enhanced weathering of minerals have limited scalability.
As I see it, Geological CO2 storage (CCS) may be the only large-scale practical way going forward, despite all the bad rap it gets due to its historical association with the fossile fuel industry. After all, the excess C in the system came from the ground, and the ground may be the only place able to re-absorb it without significant environmental consequences.
If you look at the weight of the tech product (phone) in isolation, you are correct although not in a very meaningful way. If you look at the amount of physical material that went into the process leading up to producing that product, the quantity would amount to many tonnes of material in terms of crushed ore, fossil fuels, water consumption, chemicals, packaging and so on. A phone does not only represent its own grammes material, but an enormous tail of environmental impact in form of waste, emissions and extraction remains. (This is not to mention the human labor cost involved in obtaining some of the rare earths used, from countries with, ehrm, lax labor laws).
From an environmental perspective, CO2 sequestration for EOR (enhanced oil recovery) makes little sense, other than reducing the carbon footprint of production a bit, demonstrating the storage principle and further developing key technology.
What makes more sense is to use geological storage for CO2 captured from industrial processes other than power generation - production of cement, steel and chemicals, in other words processes that would release large amounts of CO2 even if switching 100% to renewable energy.
Also, we need some place to store all that CO2 that purportedly would be captured using DAC (direct air capture) in the future.