We're currently waiting for the new installer being developed by Eric Turgeon. It may include an option for GELI, but if not, it's likely that some community members will add support for it. The current installer, gbi, is now considered legacy, so if the community wants GELI support, they’ll need to implement it themselves. Personally, I think it makes more sense to wait for the new installer as there’s no need to implement GELI twice! :-)
While GELI is relatively simple to use, it does require the user to provide and remember their passphrase. The downside, of course, is the potential for losing the passphrase, which can be a major issue. Perhaps we should consider adding a disclaimer about the importance of remembering the passphrase? We definitely don’t want users blaming GhostBSD if they lose their data due to a forgotten passphrase! ;-)