Also jets are highly directional and you have good chance to be away from the cone.
I am not a physicist but I suspect that extremely active star turning into black hole might be much less luminous than the star itself. Accretion disks can be very luminous but this is typically for very large holes in the centers of galaxies. Because we observe these huge stars only because they are so highly active, the act of converting it to much less luminous system might be undistinguishable from the star disappearing.
I believe current models suggest that a low-metallicity stars (which are the ones who’s core can collage straight to a black hole, with no intermediate neutron star) will typically collapse with no supernova or other visible trace. High mass (> 90 SM) might lead to a GRB, but not a supernovae.
You can follow the references at https://en.wikipedia.org/wiki/Failed_supernova & the supernova wikipedia page for the gory details.
Spherical chickens in a vacuum. This would be true of a non-spinning black hole. In reality they all spin. The star was spinning before collapse. So a tiny amount quietly falls in, but the bulk of the outer shell quickly accelerates, energizes, jets form and generally the massive releases of energy blasts material away.