Our PHP build interface build the lsphp binary for you, but it cannot install required libraries for you.
The cPanel build has nothing to do with lsphp, but cPanel's script is pretty good at resolve dependency, if you build php through cPanel, it will installed all libraries required, so you do not need to resolve this by yourself. For average user it is recommended. Just takes some time. So, it is recommended to build the exact same PHP version with exact same configuration parameter in cPanel first.
If you are comfortable with resolving all dependencies by yourself, you don't have to build PHP through cPanel.
cPanel won't build our lsphp binary, we hope it could. We may be able to work something out in the future. You can also ask cPanel to provide this function as well.