What a separate range bounds
Each distinct range is independently routable, independently measurable and independently failable. One per campaign, region, product line or partner makes inbound volume attributable without caller self-reporting, which is unreliable when it happens at all.
The boundary property matters as much as the measurement one. A misconfigured rule chain on one range does not reach another, which is a containment guarantee rather than a convenience.
Where the boundary is regulatory
A number in the locally recognised format is dialled materially more often, which is the operative argument for geographic ranges in markets with customers and no premises.
The constraints are regulatory rather than technical and vary by jurisdiction and range type. Some jurisdictions restrict geographic ranges to organisations able to evidence a local address; some restrict permitted use; some restrict outbound presentation. Consequently the only accurate answer to a general availability question is that the specific range will be confirmed.
Custody
Published ranges carry accumulated value that is consistently underestimated: signage, vehicle livery, print, directory listings, contractual references and indexed search results outside your control.
Which makes custody a control question. Port-out requests are verified against account authority before action, and routing changes are restricted by role and individually attributed, because a number is identity and identities are worth taking.