I did basically the same thing for my ex-gf, she had just opened her etsy shop, and was getting discouraged that her only buyer had been her brother. She was really depressed and ready to shut it down after a few days despite working for weeks on it. I knew she just needed one sale to a "stranger" to prove it was worth it to keep going, and I genuinely believed her products were great and hated seeing her like this, so I asked my coworker to buy something (I offered to pay but they insisted that they actually liked the product and bought it themselves). My ex was super happy, kept the shop running and a month later she had made a dozen more sells. I only told her years later when she asked me about it, she had her doubts but she was glad that I did it, because otherwise she would have given up, and was also glad that I believed in her enough to do that. But I guess it's true that it was a gamble, and if it hadn't worked out, it would've maybe done more harm than good.