wrote:

I want to know what is wrong with using a five buck transformer
rather than creating a shock hazard.


** No shock hazard if built sensibly.

Smoke detectors use dropping caps all the time.


Such a scheme beats on the cap and it may go bad.

** They sometimes go open.

In fact it may short out and teach you why they do not do this.


** A fuse or fusible resistor in series with the incoming AC is wise.


..... Phil