SDP is a great example of a card that could be quite good in the right circumstance, but is way too conditional to ever be used. Due to its "at least" wording, it does not combo well with cards like Cerebral Overwriter—you only get 1 net damage extra. While that's not completely horrible, it certainly doesn't justify throwing this in your deck. So, what is it supposed to work with?
I'm convinced the only thing that could warrant putting this in a deck is Janus 1.0. SDP will double the damage of any executed routines from Janus 1.0, albeit in the weaker net damage form. This will easily flatline an unprepared runner, especially one who runs with their last click. But there are several problems with this strategy.
The first and most obvious one is economic. Janus 1.0 is arguably the most expensive piece of ice in the game right now, if one considers that Orion has a built-in way to lower its own cost. Keeping 15 credits in your pool at all times might as well tell the runner, "Hey, I've got an unrezzed Janus 1.0 on the board, and feel free to Account Siphon me at any time."
So, there must be better ways to get Janus 1.0 into play—and there are. Bioroid Efficiency Research, Accelerated Beta Test, Priority Requisition, or out of faction Mutate / Oversight AI are the most blatant, but it's pre-rezzed so you lose any hope of flatlining. Isn't there any way to make this work?
Howler seems to come to the rescue, but it too has a problem—the runner can simply jack out instead of encountering the Janus 1.0 you threw down, unless you had them already resolve a Whirlpool, or they were daft enough to walk into your An Offer You Can't Refuse while you already had SDP scored. There are too many pieces involved to ever put this puzzle together.
Of course, all of these options assume you already have SDP scored, which by itself screams "It's a trap!" louder than Admiral Ackbar. Quite simply, if you really want to flatline a runner, there are just too many easier ways.