No, that's a complete firmware re-installation that includes kernel and all packages. Incremental updates would be updating individual packages out of context of a full system upgrade.
That reddit post is waaaay out of date, the upgrade situation on OpenWrt is quite mature and trivial now. Since you're already on 24.10, you have the choices mentioned by @anon63541380 or @frollic above. If you do most of your work in the LuCI web interface, then the luci-app-attendedsysupgrade tool is probably best. If you like to do things on the command line, then owut will be your first choice.
In any case, see LuCI Attended Sysupgrade support thread and Owut: OpenWrt Upgrade Tool for more on upgrading.