If you decide to use Origin and version 1.69 then it does nothing to the game other than make it an all digital installation. If you have disks registered at the point you will not need them again and you will be unable to do a disk installation again using Origin should you ever want to use version 1.67.
The advantage of 1.69 is it still maintained and supported by EA. Instead of the launcher you will get a screen which allows you to pick and choose which of your EPs and SPs you want to load. Although it says you should load only a couple of EPs at a time loading all of them will still work. However you should be aware, because Origin is a digital service there is a possibility EA could really restrict the number of packs you can play with.
Version 1.67 is not maintained or supported by EA. Steam users and all disk players are on 1.67. Certainly with an all disk installation you have ready access to your game at all times, even offline and there are no limits on what you can have installed. As someone who enjoys building I wanted to stay with an all disk installation to have the freedom to use whatever I wanted from my packs. I am not a Steam user so can't comment on that digital service.