I'm going to go ahead and disagree with you on that one. I'm perfectly capable of using the top row of number keys without looking, just by "touch".
And I disagree too (so I agree with you ; ) : I'm a programmer since a great many years and I do touch type the numbers on the top row all the time. When you program you need to use numbers very often and, very often, you don't have to input
only numbers (it's not the same as when filling a spreadsheet). When I'm filling a spreadsheet I do touch-type the numpad (full-sized Model M FTW : ) but when I program I do touch-type numbers on the top row all the time. I also touch-type -= and ~!@#$%^&*()_+ (top row on QWERTY layouts) correctly using left or right shift depending which hand will hit the top row.
Being able to touch-type ~!@#$%^&*()_+ and -= from the top row is quite convenient because I certainly wouldn't know how to do it using the numpad : )
That said I learned to touch-type alone and wasn't aware that there were two schools as to how the '6' had to be hit: I hit it with my right index and it's been too long to change that. Most split boards seem to have the '6' on the left side of the board (I've got an old Belkin rubber-dome here where it's not the case: the '6' is on the right, but I don't use that board). I like those that have two '6' keys so that everyone can be happy (honestly I don't know which one is the one true correct location for that key on a split keyboard: I simply learned that way and got used to it).
Funnily enough my current daily driver is a Swiss-german QWERTZ Model M that I use as a QWERTY and besides '5 %' and backspace there's not a single key of the top row that corresponds between Swiss-german QWERTZ and QWERTY so being able to touch type that top row surely helps

I'm also pretty certain that people using blank keycaps do touchtype the top row without any problem ; )