While you have to start somewhere, this illustrates the larger point. Some basic facts about the scale of the problem remain:
"The total volume is approximately 1.3 billion cubic kilometres (310 million cu mi)[7] with an average depth of 3,682 metres (12,080 ft).[8]"
> 3x10^8 cubic miles vs 3x10^3 instruments
> Instrument cannot reach even ~average depth
> 10 years of data
Certainly, it is a start. But...
There is a huge amount about the oceans that we do not know and cannot measure with requisite precision. Understanding the difference between surface temperatures and the actual thermal potential of the earths oceans are two different tasks. EG, due to sub-surface thermal venting there are many areas of the deep ocean that don't at all look like surface temps. {etc} So there is huge potential for the oceans to do unexpected things. For all we know, plate tectonics may be driving huge amounts of thermal energy variation in the deep ocean...and a "proper climate model" would likely need to understand this at some stage. This really goes to the core of the question of the oceans as a heat-sink.