My black leather jacket

[Gene]

 Is there anything wrong with treating it with black shoe polish?

[Bob H]

I wear Hi-Viz textile jackets & helmet. Spray it yellow!
Seriously, being seen is super important to me. It is no guarantee, but I try to stack the odds in my favor.

I really like a discontinued Tourmaster series 4 jacket, looked on Ebay and picked up an open box one for half price. Another one of my textile jackets is mesh (Hi-Viz) which is great this time of year.

I would save the black one for a cool looking jacket, but I won't ride in one.
I have almost pulled in front of a blacked out Harley dude once, and I LOOK for motorcycles.

[mollusc]

Shoe polish tends to rub off against other things.  I wouldn't use it on a jacket.  There are other products that work well to rejuvenate leather clothing and help keep it supple.
I have an off-brand (Power Trip) leather one that I wear in winter, but it has reflective visibility strips on it.  In warmer weather I ride in my hi-viz Tourmaster mesh, BMW Motorrad, or Fieldsheer mesh, depending on conditions.  They all have reflection built in.