I know what you mean. I would suspect that the bulbs are 1/4 watt at best. Probably between 3 and 7 watts.
I saw a review on amazon where a guy measure it with the light meter on his multimeter at 750 out of 2000 max, said he had measured the lights on his 4ft tank at 500 and a cloudy day at 350. Might work OK for plants. I would just add cuttings from thinning to see what it does with higher light needing plants. I saw that it supposed to be 9500K.