Shortly afterwards, Da5id tries it, and suffers the consequences.
Da5id is the first and, so far as we know, only character to try the Virtual version of Snow Crash. All our other experiences with it involve the Physical version.
It is fair to say, based on our sample size of two (Da5id and Hiro), that the Virtual version relies upon the susceptibility of hackers to curiosity and a feeling of invulnerability, or to involuntary exposure (as Hiro is threatened with later, or via the benefit concert). It's not designed to get you hooked; it's designed to wipe you out.
We later see characters who seem to take the drug repeatedly. Why?
What are its positive or attractive effects?
Juanita explains this (page 200):
"It's not a drug," Juanita says. "They make it look like a drug and
feel like a drug so that people will want to take it. It's laced with
cocaine and some other stuff."
and, as Hiro later explains to Ng/Lee/Enzo (page 404):
"Here in the First World, everyone has already been vaccinated, and we
don't let religious fanatics come up and poke needles into us. But we
do take a lot of drugs. So for us, he devised a means of extracting
the virus from human blood serum and packaged it as a drug known as
So - it's positive effects are exactly what you'd expect from a cocaine-based drug which has been mixed properly, in a controlled environment, with other drugs designed to make it a pleasurable ride and landing. (Unlike your corner drug dealer, L. Bob Rife is probably paying people to process it with quality control, not just diluting it willy-nilly to improve the margin.)