That's basically what ultimate team is in practice.
If it had no cash involved and was either tuned to a level where a normal person could build a team that was competitive at the high end in a month or so (since it is, ultimately, an annual game) or you just had a budget and could sign who you wanted (based on "market value" that was set based on overall rating and position or that fluctuated with how many people had a guy on their roster), it could be awesome.
But yeah, it's basically a card game (that I think also has cards expire, though I don't play it at all) that's designed to milk whales for cash. And they replaced a lot of the normal Madden tournaments you could win money playing to use this nonsense mode instead.
The only semi-saving grace is that it's mostly self contained. There are obnoxious ads for it, and other game modes haven't seen the development work they should because they spend most of the non-engine work on that nonsense, but you can still just play online head to head of a great football sim if you tune out the nonsense.
It's super scummy and I would love to see legal involvement shut it all down. Lootboxes are unregulated gambling and in sports games specifically they're very obviously targeting kids.