Amazon isnt a great source for diy electronic components.
digikey, arrow, future electronics are the ones i would recommend for this.
the bridgelux strip i linked a few posts back is just 83 cent and provide 156 lpw, thats not bad for the price.
the recent bridgelux strips are almost a third better but 5 times the price iirc.
there is a whole thread about the arrow offerings.
I built 750watts of lights with samsung H series strips about 3 years ago when diy strip building was quite new and quantum boards had just came out. They have been fantastic for me and very satisfied with them. I am expanding my space and started looking at current led options, quantum...
www.rollitup.org
sometimes they also offer very cheap "delta" drivers.
one can make a hell of a deal there with some luck.
sadly i have no overview how the european market is atm for ready made lights, or if there are comparable offerings.
as i dont know which leds are used in these 50$ amazon lights its hard to make any claim, but i would bet theyre easily also the 150lpw league.
regarding the safety concept, there are so many bulbs out there, but not only a few have 2 solder joints in the middle which is straight on your mains.
also its specified, normed, if they dont offer a galvanic isolation by a transformer they need to be enclosed in a plastic enclosure, same is true for pretty much all common electronics.
lots of people use bulbs opened and i never read of real world problems, still with a cheap driver you get quite some safety for free and be in the norm, beside that it converts your power more efficient in first.