Interpretation, nothing more.
HS2 might "serve a lot more than 100 miles", but only in that trains running longer distances might use it for the 100 miles (or thereabouts) closest to London in order to shave a few minutes off their overall journey times.
Consider journeys beyond the first 100 miles, eg. Birmingham to Manchester or Leeds (aka the former Phases 2a and 2b of HS2).
Please could you explain how much journey time will be saved along these sections, as a result of being served by HS2? After all, you've presented it as serving "a lot more than 100 miles"
I'll give an example.
If the full HS2 project was built Southampton to Newcastle would have seen minimum journey time improvements of 60 minutes of time saving whilst changing trains twice using existing timetables (i.e. no direct services between Southampton and Old Oak Common), even though neither location was even close to any HS2 (closest section of rail proposed by HS2 was over 40 miles from either).
For Phase 1, the answer depends on where people are travelling to/from.
For a lot of people travelling it'll make their journey around 30 minutes faster, as they'll be travelling to/from London.
Obviously for those travelling between Penrith and Lockerbie, it'll be of limited benefit - although the numbers doing so would be insignificant compared to those doing the shorter trips.
Of course, that's all assuming train frequencies don't change. If by building HS2 there's scope for 2tph rather than 1tph the savings could be that the train gets you to where you want to much closer to the time you want.
Let's say you want to be in Glasgow at 9:00 for a meeting at 9:30. If the current train gets you there at 8:10 or 9:10 that's either a long weight from stores or being reliant on the train being on time.
If that then changes to be 8:10, 8:40 and 9:10; then you've gained 30 minutes at home and still able to be have a shorter wait upon arrival.
A lot of these other benefits aren't yet defined, as they are future projects (there's been examples of the sorts of things which could be done, but almost nothing confirmed).