GrowCNanswered grow question 4y ago I agree. False or "stretched" advertising is not cool. Low cost lighting is one of the worst offenders.
A 2'500 watt grow light is an obvious marketing lie. Most home electrical circuits can't even provide that much wattage. But manufacturers still lie and many people believe the lie and buy their lights so they keep doing it. Hey, if you can buy a 2'500 watt light for 0 why would you buy a 0 light that is only 300 watts?
Breeders stretch the truth on grow/flower time.
And every few days a new grower is on here asking why their first grow is taking weeks longer than the seed specs say. A professional doing hydro and hitting conditions exactly might get the rapid growth cycle advertised but most can't.
The inflated grams per watt numbers is another stretching of the truth. They just don't tell you that they are professionals, growing in hydro and veg for a really long time to get a huge plant. They can technically get 2.5 grams/watt. It might not be the most efficient regarding time, space, or electricity consumed and almost nobody grows like that. But it can be done.