This is a tricky answer. The default random function in many environments is poor (see other examples given above and below), if you are generating a unique id using a PRNG and think in terms of the birthday paradox, then you should also be concerning yourselves with the quality of the random generator. While it is unreasonable to expect every developer to know the ins and outs of a deeply technical issue, defaulting to using a known good (enough) algorithm like MT over making an assumption about the quality of an unknown algorithm (unknown at least until you looked into the source code) just because it came from google is poor engineering (IMHO)

The analysis in this article was great engineering - something that in my experience often happens after poor engineering... YMMV

It was dependent on it being a CSPRNG which it wasn't. Math.random is designed for things like games and animations where randomness isn't critical and performance is important.