Both statements could be true - I wouldn't be too surprised to see Apple stretch the truth; yes, it's true, performance on a 25 second boot (my iphone 6s) from cold was improved to 24 seconds. Doesn't really move the needle, but still true, to some degree. A second here, and a second there - starts to add up though, particularly on boot up, for those of us who end up doing that multiple times a day.
Also, in general, any time you can remove code from a system, that isn't contributing in any meaningful way, is just a good thing to do - both from reducing attack surfaces, as well as general reduction in code size, and the advantages that come along with that.
