The big difference is that only one of those ports (the TB1 port) can be used to adapt and daisychain all possible kinds of peripherals...
Not quite true, as Firewire can daisychain.
As laptops have become lighter, MagSafe probably has become a bit less effective. And offering a MagSafe cutoff at the end of the USB-C charging cable would probably be more fiddly and less effective as well (I simply cannot see MagSafe and USB-C charging to ship on the same laptop, among other things this would require two charging cables).
Less effective doesn't mean ineffective, and just because USB-C (at least theoretically) *can* support charging does not mean that it is obligated to: Apple could have elected to have incorporated a MagSafe dedicated to power...but chose not to.
FWIW, something that I think people are missing on this en masse conversion to USB-C is that while it has great promise for both a universal plug format as well as high bandwidth .. not all devices actually need high bandwidth.
As such, while one can use USB-C to power a keyboard or mouse, to actually do so is grossly underutilizing it, which devalues how much it is actually worth when there is no "lesser port" present to use instead.