Mainnet costs real DASH. You bring the funding key yourself — this page never generates a wallet that holds your money. It does generate the new identity's keys, and if you lose that phrase the identity is gone.
Everything you do here happens under your own responsibility. Nothing on Platform can be undone: credits you move, an identity you mint and a name you register are final, and a lost key cannot be recovered by anyone. evotools is free, open source and offered as is, without warranty — if something goes wrong, the loss is yours.