First of all overtly trying to tank is bad precedent when you've got so many young guys (and this is the youngest Spurs team in decades). You want to instill a mindset of discipline, optimism and professionalism. Tanking is for loser franchises. It brings a mindset that losing is okay. I am against it on principle. Really anything else in this discussion is superfluous.
Secondly, as they'd likely be a mid-lottery or lower lottery team, I'd rather have the Spurs organization reap the income of another playoff appearance. You want your small market teams to survive in their current cities so, all this helps. And if they do somehow get a high lottery, well, unfortunately this is a weak draft. There are no sure things even in the top 5 (or so I read, I don't follow college ball.)
If DeRozan walks, he walks. Or maybe he opts in or maybe they do a sign and trade. I'd almost rather have salary cap than flotsam from a trade. He's not bringing back anything amazing.
Anyway, tearing it down always takes time like 5+ years to rebuild, often decades. You never know when you'll get out of it. So, yeah, I'd rather get the PO record to cap our run before the coming doldrums.