Is the disc drive the only difference between Xbox One S and All-Digital Edition?

Is that it?

Pretty much; the only real difference between the Xbox One S All-Digital and the regular Xbox One S is the removal of the disc drive and the disc drive eject button. It may seem like a subtle change, but it has a few implications for what you can do with the box, along with the price point.

The discless Xbox One S All-Digital Edition should end up being around $50 cheaper than the regular S, and comes bundled with three games — Sea of Thieves, Minecraft, and Forza Horizon 3 — making it a cost-effective option for gamers wanting to jump into the ecosystem for the first time. While the RRP for the All-Digital is $50 lower than the regular S, it remains to be seen how retailers will position the consoles. It may be the case that you can still get regular S bundles for cheaper.

Disregarding price, without a disc drive you lose the option of buying 4K UHD Blu-ray movies and shows on disc, and you lose the option of buying physical games either for the sake of collecting or trading-in when you're done.

Both Xbox One S consoles, along with the Xbox One X, sport a range of digital 4K offerings, including Amazon Prime Video, Netflix, YouTube, and Microsoft's Movies & TV platform, but support for UHD media has generally been better on disc, so far, as companies battle for licensing rights to the digital versions. Games however will output at an absolute maximum of 1080p across both systems. If you want to get the most out of that 4K TV set, you'll need an Xbox One X instead.