FWIW, Sparrow (and Nunchuk) displays the would-be fiat conversion as well. A noob could still experience seeing a fake $10 grow to a fake $40 in a year; then think to themself: "I sure wish this was real BTC".
Discussion
Yes, I got 500K Sats from the testnet mempool faucet:
I have 1.25M Sats 🎉
I have $1,219 of fake money 😂