Yes, the recipient really gets fractional shares of stock in a real brokerage account.
The amount they get depends on the gift card’s face value and the stock’s closing price the day the gift card is redeemed (subject to a cutoff time of 3 pm ET, or a little earlier on certain holidays).
For example, if the recipient redeems a $50 gift card on a day the stock’s closing market price is $100, they’ll get half a share of stock, which will then go up and down with the market. In our example, if the stock price goes up 10%, the recipient’s 0.5 shares will be worth $55.
As a shareholder, the recipient will receive dividends announced by the company (prorated based on the fractional share they own). The recipient also receives voting rights once they own at least one whole share of stock.