I don't think being free matters as opposed to literal pennies. The prizes are far too low relative to the costs of investment.

Who's going to spend $400 to win a $20 top prize (if even that.) (Yes, you can resell the deck, but I don't buy that argument.) You can also rent for cheaper, but then it's not exactly free.

The argument given to me before was that you can play more than just one tournament. This is a game, not a job, and people have lives so it's equally unattractive.

$25 cost for 2.5k prize. Now, that's attractive. Can splinterlands support a format like that? Idk. (Haven't tried the one on MTGA, but won't be surprised that one day I will.) If Gods Unchained wasn't on eth, think I would've tried the draft mode too.