Exactly, the first GS for Philo costs 17 turns, but the next (in the example) will only take 5 turns under Caste/Pacifism (double civics switch) and time nicely with Bureaucracy for Academy. Also, Philo can be a useful trading chip. I don't have any hard rules on this though. Caste/Pacifism is more likely to be useful early with a small/developed empire. With extra space and a bigger rex, slavery might be more beneficial, and aggressive bulbing is less likely to be vital when you don't need to strike in the early Industrial era, and you just have to stay in sight of the AI in the tech race. In general I only settle if I expect the tech rate to be weak for a long time and the scientist may account for a significant percentage of beakers (Classical era warfare for example).
Even with the 1st GS spent on Philosophy, though, I see one scenario where delayed caste system may do better than non-delayed.
Say, for example, you wanted to win the Music race, but with minimal risk. Then to open the Philosophy bulb you take Drama instead of Code of Laws. Once Drama is finished (hopefully you've timed your 1st GS to come out at the same time), whip out a Theatre in a border city and switch to Pacifism (the 2nd civic in the pair is yet to be discussed). Then run 2 scientists and 2 artists in the border city. With Pacifism, it should come out in 9 turns. During the last few turns, if no one has Music yet, tech Literature.
Now, there are 3 possiblities:
1) You get a Great Scientist. In this case, proceed with the game plan you would have taken had you not tried this gambit.
2) You get a Great Artist, and no one has Music yet. Now is your chance to reap your reward. Since Music is only 3rd on the preferences list, after Literature and Drama, you move it up to 1st by teching Literature. You can bulb Music and get another Great Artist for free, effectively gaining yourself a free tech.
3) You get a Great Artist, but someone already has Music. This is the worst case scenario...but it's not that bad, actually, as you can save the Great Artist for a Golden Age.
Now, the tricky part is deciding which civic to use instead of Caste System. If there are some fast-teching AI neighbors, you might be able to gain Feudalism in trade, opening up Vassalage. The default option is Hereditary Rule, which you can unlock by trading for Monarchy.
Once you have Music, you can use it as trade fodder to get some more useful techs, while keeping your free Great Artist ready to start a Golden Age when the time is right.