It's really very simple.
Tanking breeds a losing mentality and disrupts team cohesion, making it harder to shift to a winning mindset in subsequent seasons. Besides, high draft picks come with no guarantees of success.
Nothing tops building a winning culture. Create a competitive environment whilst you develop some hungry young guys competitive environment, and build a culture that is founded on sustainable growth.
The funniest thing about the obsession with tanking around these parts in recent years, is that this franchise has seen the perfect examples of what winning "pointless games" can do in the long run.
2012: started 2-8, then rattled off 5 wins in the last 6 to close out the year. Following season? 12-4, and a divisional round appearance.
2014: started 3-8-1, rattled off 4 wins to close the year, snuck into the playoffs for another divisional round appearance? Following season? Yeah, you get the picture.
There's no such thing as winning pointless games.