This does not sound like a very exciting feature. I understand its use and necessity, but it doens't sound that exciting for a language that is being accused of being "in the past."
Disclaimer: I currently do and have used for some time PHP at my job.
Some people use the PSL to determine what is a valid domain name and what isn't. This is dangerous, particularly in these days where new gTLDs are arriving at a rapid pace, if your software does not regularly receive PSL updates, because it will erroneously think new gTLDs are not valid.