Right, but that's the inherent problem with these arguments publishers are making. "It's ethical because players always get something of value" and "none of these digital items have value" are incompatible. Most of the common items in lootboxes are essentially worthless, and publishers know this because the system is designed that way.
It's not necessarily an oxymoronic argument, as "value" has different meanings in the two statements.
"Players always get something of value" is a legal requirement in some jurisdictions when it comes to loot boxes--you have to get
something, you can't get
nothing. This is why games tend to include a conversion mechanic that doubles as a pity mechanic (e.g. disenchanting Hearthstone cards into dust, or maxed out Clash Royale cards converting into gold).
"None of these digital items have value" refers to real world monetary value, as in you can't sell them for real money. Companies like Valve and (it seems like EA? not familiar with FIFA personally) skirt this by allowing player-to-player trading, which breaks the supposedly closed loop economy, and effectively turns it into real gambling through the gray market.
"Most common items are useless" tends to be true, but it's not endemic to lootboxes. Good lootbox designs will still ascribe value to common drops.