sizzling :
webworkings :
It may seem 'easier' to download it, like with so many things, but it is also so 'easy' to lose it or lose access to it when done that way as well. Just saying.
How exactly? I'm far more likely to loose/damage a disk or physical copy of the key. I buy all my games through Steam, Origin or Microsoft, as long as I have access to my accounts I have instant access to download and install any game I have previously bought.
Companies can and have gone out of business. Sometimes even when they're still in business, they drop support for older products. Have you tried getting updates for a new install of Office 2003? The website for old Office updates no longer exists. You can only get them through Windows Update by enabling "Get updates for other products the same way I get updates for Windows." Which presents a conundrum if you quickly need Office 2003 updated, but don't want to waste time updating Windows.
Also note that your Steam account is not transferable (unless Valve specifically authorizes it). When you die, the licenses to all those games you bought go *poof*. No way to give collectible classics to your kids as an inheritance. No way to give away games you no longer play but might be entertaining for your kids or friends.
The buy to own model works (physical copy of games on disc). The rent to subscribe model works (Netflix, Office 365). The buy to subscribe model (Steam, Origin, etc) still needs a lot of tweaking before I think it can legally be considered the same thing as owning.