I disagree. I think the Titan is a gamers card because it doesn't duplicate Quadro or Tesla functionality - keep in mind that most professional 3d applications require specific software drivers and firmware to be used, and on that note the GTX Titan does not support 10 bit color in adobe suite so it isn't all that useful for photo or video editing. This is also true of 3DS max and other software suites. They require specific software drivers and firmware for full functionality, generally speaking, which geforce does not provide. Quadro and Firepro do. That's why they cost more - the firmware, drivers, and support. There's a whole other level of support that comes with Quadro cards which a Geforce doesn't get.
The Titan is a gamers card for extreme surround gamers. 6GB of VRAM. That's how nvidia marketed it. It was the "ultimate gaming card". You can look at their launch slides and what not and they marketed it as a gamers card, not as a professional card. Again - Titan DOES NOT duplicate quadro functionality nor does it come anywhere close. That's the key point here. In order for Titan to be taken seriously in the professional context, it has to offer more than CUDA. And it doesn't offer what Quadro or Tesla do in that respect nor is it in the same stratosphere.
That said, it is useful for CUDA development. It is not gimped in that respect, so it will be useful for someone in that context. But in other contexts the Titan definitely does not replicate Quadro or Tesla.