At just under 40 minutes to Euston that's comparable to Guildford (45 minutes), there's lots of business located in Guildford who are there because they can get their staff to London when they are needed for meetings but with lower office space costs and not having to have all your staff needing to get to London (which reduces costs for cleaning, admin and lower grade staff who never/rarely need to attend the meetings in London) and for those staff who do they aren't going in every day and even the data which they do they aren't always having to do so at peak times. Also as travel is a business expense this gets passed on to the clients without the company having to absorb it in their overheads or the staff having to pay it or of their own pockets.
Guildford isn't an isolated case, at I'm sure that it's similar for Reading, Milton Keynes, Oxford, Bristol, Basingstoke, Farnborough and so on, basically anywhere within an hour by train of London.
As a case study there's a district council which has 3 stations which are within an hour of London and are seen as a commuter area for London, yet about 10% of workers do so. The vast majority work within the borough or in nearby boroughs, with there being a lot of companies using it as a base to access London as required.
However it's not just London which it would have easy access to:
East Midlands Hub, 17 minutes
Manchester, 37 minutes
Leeds, 46 minutes
Newcastle, 49minutes
With that sort of national reach I can see that it will allow companies to have one main office rather than several small satellite offices, which could be fairly attractive to smaller companies (bearing in mind that most people work for a company which had less than 250 staff).