What it means
IPv4 scarcity often affects address pricing and allocation. A public address can make a service reachable, but reachability still depends on routing, firewall and application configuration.
For hosting
Confirm included addresses, reverse-DNS control and any extra-address terms. An IP address does not by itself establish reputation or guaranteed mail delivery.
What is included with the address?
Check whether the address is dedicated, whether reverse DNS can be changed and what an extra address costs. Mail reputation and application reachability need their own verification.