There are a lot of companies based in CMK, and folks from the broader region are basically forced to drive. Now, if you live in Bicester, or Bucks (Winslow, hopefully Aylesbury one day, a big place with not much going on and a **** London service too) - there will be inbound railway.
It also links folks to a main stop on the WCML, with hourly services to Manchester and Liverpool, and others (West Midlands is well served from Oxford and Bicester) - and access to Northampton and the Trent Valley stops too. There is also football, gigs and a massive shopping centre with a JL. Not much more admittedly, vs similarly sized cities, for cultural pursuits.
Oxford also has a lot of jobs, education of course, and then cultural/leisure/tourist appeal too. Cambridge is the same, with even more tech/bio growth. There will much outbound and inbound from those key nodes, and actually Bicester too - tons of shopping (foreign and Brit visitors) which creates many (admittedly fairly local) jobs - but it's also a very fast growing town where you could in theory work in London, B'ham, Oxford or MK (with EWR) comfortably, so a lot of opportunities and a great location.