The discard effect from this doesn't happen until the end of that turn and it is on the seven new cards not the old hand meaning you need to rawdog the thing you want in the bin or have used a Brainstorm or Vampiric Tutor style thing to set it up
That said, we have plenty of other mana rocks, and this one feels the least impactful
However, I will give you some suggested commanders for these cards
I think I saw him borrowing some cards from some generous guys before the tourney started, so his deck was a little slow and he was still a little new to the game
You can remove any number of +1/+1 counters across all artifacts you control to add that much mana to your mana pool, and then Jetfire, Ingenious Scientist transforms
Not every LCS will want to give space for 100,000 dime cards, but some of these LCS's have the ability to turn their inventory frequently, with the amount of people that come through their doors looking to sell