I agree that old computers, or for the matter of fact several old electronic devices can re-purposed to serve some task; but one main conflict of interest I find against it is 'power-efficiency'.
If we're aiming for planet friendly activity, we should consider saving power as well & A cheap 7th Gen intel U series CPU or AMD G series APU is much more power efficient than the intel Core 2 Duo.
Apart from huge leaps in performance, the associated ecosystem of electronics with it is power efficient as well.
With everything moving toward the web, increased performance doesn’t really make a difference in a lot of use cases. The biggest performance hit is usually slow hard drives and lack of RAM. You can still get away with 4GB of RAM
I agree that we can do 'something with' that 12-15 years old laptop; but that 4 GB DDR2 is wasting power which can be saved by using 7-8 years old DDR3L or 3-4 years old DDR4L.
I used one. It’s much worse than my Core 2 Duo from 2009 with 8GB of RAM, the screen is smaller and it has a lower resolution (1800x1200 vs 1920x1200). It feels much slower.
As an off topic aside, of course it’s much worse than my $379 2018 iPad with 2GB of RAM.
If we're aiming for planet friendly activity, we should consider saving power as well & A cheap 7th Gen intel U series CPU or AMD G series APU is much more power efficient than the intel Core 2 Duo.
Apart from huge leaps in performance, the associated ecosystem of electronics with it is power efficient as well.