I would ABSOLUTELY argue that you more own a game purchased on gog, with an offline installer, than one purchased on steam. I now see the functional difference between owning a drm-free installer vs owning a physical game, but there’s also a gulf of difference between steam and gog
Just to be entirely fair. The rest of what you said is absolutely spot on.
Depending on your perspective, the sell/trade/loan aspect of physical can be a huge deal. I outlined in another comment, selling/trading games was never my thing, but it was my cousins. From my perspective, there’s marginal difference, but there IS a difference.