It's not about cost, it's about accountability. When Apple discovered their chargers were faulty, they emailed everyone they knew who had one and spent years replacing them all (remember those green dots?). While many argue it took too long, but Apple did accept responsibility when some of their Macbook batteries caught fire too and made it right.
What the hell is "Cooliggs" going to do if their batteries start catching fire? Do you think they'll investigate the causes, determine all affected customers, proactively notify them, and offer replacements? Hell no. They'll fold up, make up another name, and continue selling the same batteries. All these fly-by-night Shenshen brands are the same. They're not in it for the long term, they don't care about being accountable at all. It costs them less to just make up another bogus brand name than to fix whatever is wrong. Cooliggs doesn't even have a website!
Even if the batteries are all coming from the same assembly line, iFixIt is a U.S. company with a valuable brand that they've built up over a decade. If something happens to go south with their batteries, I am confident they will investigate it and make it right for those affected. They'll do it because they're invested in their brand, and thus accountable. But because all of that is expensive, their quality control is probably better too. Again, they don't want to tarnish what they've spent so long building up.
If that happens to cost more, so be it. When it comes to a potential lithium chemical fire next to face or on my nightstand while I sleep, I'll pay the extra $$ for good brand.
