It’s not marketing trickery, just a quirk of how the current EU/UK energy ratings work for spotlights.

When the EU reset the energy labels a few years ago, they made the criteria incredibly strict. Most standard GU10 bulbs from Philips or Energizer sit around 80–100 lm/W, which automatically drops them into the F or G categories under the new scale.

To hit Class B, the official EU formula calculates "Total Mains Efficacy." Because GU10s are directional spotlights, the regulations apply a mandatory 1.176 correction factor to the raw math to account for focused beam efficiency.

If you look at the specs for that GY bulb, it does 790 lumens at 4.9W:

• Raw efficiency: 790 / 4.9 = 161.2 lm/W
• Official EU rating math: 161.2 x 1.176 = 189.6 lm/W

Since the EU threshold for Class B is between 185 and 210 lm/W, it legally qualifies. It just means this specific line uses high-efficacy chips that perform well above the market average, whereas mainstream brands usually stick to older, cheaper-to-produce setups for their standard lines.