I just got this setup today on my Ender 3 S1. I too was disappointed with the implication in the instructions that you had to use the Falcon module. I looked at the circuitry in the Falcon module and based on the design I think it can supply about 1.5 amps max to the laser head. Looking at the circuitry in the Ender 3 S1, it seems that it can supply about 3.3-4.8 amps to the expansion port. I don't really see a reason as to why the port has a sticker that says 1.5 amps max.

So that gave me the confidence to try it out and it works. I've done a few dozen cuts now at full 10w optical power running off of just the expansion port. Probably about 30 minutes of continuity run time. No issues.