It means that a business that needs to occasionally meet people face to face in London can instead be based in Crewe, saving £10k a month in rent and saving in salaries.
Now what happens when the business needs to meet someone face to face in say Cambridge, home to a growing number of tech companies? Our current rail network is so London-centric that the fastest way to do that from Crewe is to go all the way south to central London, turn around, and head north again in almost the same direction you came from. One of the big advantages of being based in London is that you can get to nearly any major city in the country quickly and directly by rail, and HS2 just strengthens that advantage.
The expertise brown from HS2 needs to build Birmingham east to Cambridge/Norwich, and south west to Bristol/Cardiff, as well as Liverpool-Manchester-Leeds
Why would I, a business owner, want to pay extortionate rents for floor space in London when I could instead have an office in Crewe for 1/10th the price and still reach my clients when I need to?