Using static IPs is usually not necessary. In certain cases though, IP auto-assignment fails. Sometimes you have several networks on your computer, and the netmask will be mismatched between the computer and tablet. Regardless of the reason, setting static IPs is only recommended for advanced users or for last resort troubleshooting.
If you are using an ad-hoc network with dynamically assigned IPs and Lemur is working good, you will not see any performance improvement by using static IPs.