One upside of the laser or LED rescue light (flare substitute) is that it burns for 24 hours or more.
A good rocket is more visible than the LED, but only for about half a minute. If nobody happens to be looking in the right direction, then the flare is unseen.
If someone actually sees a red rocket, will he/she have a bearing on it? Probably not. When one is seen with no follow up, how sure is the observer that there is something there?
A flashing SOS that goes on and on seems more likely to attract attention.
I'll go for the 21st century technology before the Victorian one.

We have read lots of theory on the electronic vs pyrotechnic flare. Does anybody have stats of number of rescues due to use of pyrotechnic devices? I read all I can on sailboat failures, sinkings etc and have yet to find an account of a rescue where pyrotechnics played any part, far less a major part.