A $500 won't even get you proper training or a certification from the vendor of that massive tool and/or service that your business relies on, that's why it goes unused. It's large enough that you feel like blowing it on a Coursera course or a book feels too little and small enough not to be of actual importance.

Can I blow it on books? That sounds like enough for two of the ridiculously overpriced books I constantly eye.

Dang, what kinda books you eyeing?

Knuth's set was the most expensive one I've bought recently

I suspect these benefits are pretty cheap to offer, at least most years. my employer has a fairly generous tuition reimbursement benefit, but people rarely use it. most people don't want to slowly chip away at a degree on top of a full-time job.