If you fancy Sport track, then the advent of digital will affect you only a little.
Also bear in mind that Scalextric digital is the best part of a year from the shops.
The basic track will remain exactly the same, needing only lane changers if you choose to use them. Of course, you will then need digital control equipment too.
You can go ahead and build it and enjoy it, then add the digital equipment later, IF you really want to make the change. I truly wouldn't put off building a track for that reason, absolutely not.