Cheap Cobs?

I found these on Amazon. https://www.amazon.com/Spectrum-Relassy-Waterproof-Natural-Dissipation/dp/B07CMTJW5T/ref=pd_sbs_86_5?_encoding=UTF8&pd_rd_i=B07CMWMXXS&pd_rd_r=23f4a56b-9c12-11e8-9964-87cf98f5eb50&pd_rd_w=56O41&pd_rd_wg=lKLUC&pf_rd_i=desktop-dp-sims&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=f9e73f8b-e90f-46a6-8123-a09c49edb7a8&pf_rd_r=2WDBJ0YJ2G63EZYX56HP&pf_rd_s=desktop-dp-sims&pf_rd_t=40701&refRID=2WDBJ0YJ2G63EZYX56HP&th=1

Waterproof 100W LED Grow Light Full Spectrum, New Technology Cob Led Grow Light, Natural Heat Dissipation Without Noise, Suitable For Plants All Growing Stage Indoor Or Outdoor

About $35 each.

Specifics:
1.Model No.: CF-UT01
2.Power: 100W(wall draw power 50~55watts),
2.Case color: Black
3.Wavelength: 380~780 full Spectrum
4.Waterproof: Yes, IP67
5.Input Voltage: 120Vac(optional) 6.Frequency: 50Hz/60Hz
7.COB Led Brand: Bridgelux
8.Flux Lm: 5000lm
9.Lifetime: 50000hrs
10.N.W: 0.6kg

They are available in several different config's, 50, 100, 150 watt. Wall watts are considerably less.

Seems like a good deal for small grows?

Why are they calling it 100 watts when the actual wattage is 50-55 watts?

There were critical reviews, including one that said don't use for cannabis.

I suspect the max wattage of the COB is 100 Watts but they run it lower to get a better life. It's "advertising" or more precisely Lying. They have a 3X150 Cob array that they call a 450 but it only draws about 250 wall watts. My concern would be that the coverage would be too small at a decent umols.