The alternative to spending X minutes waiting for a CI build is spending slightly more than X minutes executing a manual build with a nonzero chance of time-wasting mistakes, not doing nothing.
Not waiting for a build means not testing it, in which case a manual non-build of an uninteresting software configuration seems attractively elegant but a CI system still provides value by recording that a certain configuration compiles and by making the built application available for later use in case it's needed.
That is indeed true, CI is way less error prone, thanks. Having a build ready to go is quite handy too.
What do you mean by "not testing it" "seems attractively elegant"? Testing a build is still a must, although that ends up to be manual testing usually (unit tests don't assure much, integration take a lot of engineering effort for setting up and writing, especially if they were not taken care of from the start).
Not waiting for a build means not testing it, in which case a manual non-build of an uninteresting software configuration seems attractively elegant but a CI system still provides value by recording that a certain configuration compiles and by making the built application available for later use in case it's needed.