That way you can respond to their range with something along the lines of "that sounds roughly what I was expecting", "okay, I'd probably be looking for the top end of that", "that's perhaps a little lower than I was expecting - is there enough room for flexibility for us to be able to continue talking?" or whatever. It's too early in the conversation to be doing a full salary negotiation, you're just making sure the role's at the right level.
There's a big problem with employers writing a senior-sounding job ad for a junior role - the salary range is a much more accurate indicator than a job description.
Disagree, I've had "my range is X-Y", and the recruiter told me "for this role the range starts at Y+20%, are you ok with that".