Underwater lights - are they worth it?

Don't mean to throw out a sales pitch,, but I do have a fave brand not mentioned.

We sold, installed and upgraded many Aqualuma lights for our customers. The one-piece polymer housing lens / shell is bomb proof.

Over 5 years ago, one customer, many years after original purchase, tapped on us to upgrade their lights, not from failures, just the technology had improved and the new lights were multi colored and brighter.
All serviced from inside the hull. No haul required.
That's when we got involved with the company.

Not many folks know of this Aussie brand but well worth a look.
PM me if you need details.

What brand & model do you have now?

I had this on a 70 johnson years ago. The yard did a mounting block out of fiberglass. Easy to do with Coosa as well

Easy to make. Take some 2” coosa, epoxy two pieces and cut at an angle matching the transom. Epoxy on the transom. Install the lights.

I can think of a couple of boats that I've seen with a similar transom.
Both from small Italian builders, whose name is irrelevant, but I can see why you find that unusual, anyway.
In the cases I'm aware of, it was a sort of builder's afterthought, driven by the market demand for extended swim platforms.
Which is more easily addressed by making an additional mould for it, and then bolt it to an existing hull transom (fairing the joint with filler and gelcoat), adding also a bit of static stern buoyancy in the process.
Maybe that's what also Mikelson did, 'dunno.

Back to SoCalD question, I wouldn't bother doing anything at all, because the u/w light effect can be even nicer, when they are angled downward.
So much so, that I've seen downward angled blocks made as Pascal suggested, but for the opposite reason, i.e. to point downward the lights installed on a more "normal", almost vertical hull stern.

I mostly use them pointed towards the bottom, for two reasons: firstly, most of my preferred anchorages are in no more than 20 feet of depth, and secondly all of them are in crystal clear water.
Consequently, by hanging a pair of diving flashlights from the stern cleats at 8 or 10 feet from the bottom and pointing down, you can create a very nice effect of being floating "suspended" on an illuminated seabed - without being disturbed by direct light, as can happen if you are swimming behind normal stern u/w lights.
But in principle, you can point the flashlights as you prefer, depending on where you tie the hanging line to them, and possibly using also some fishing sinker attached to the side that you want to keep down.
For instance, I experimented with the opposite of what I previously said, i.e. hang the flashlights at 6 or 8 feet from the surface, pointing upwards and illuminating the hull.
Which also creates a nice lighting, but not as "soft/distributed" as with the lights pointing to the seabed.