The Tesla's were targeting graphics professionals like CAD Engineering or Architecture where there is a need to display large files without any hiccups.
The Tesla cards have no video outputs. They support no monitors of any size.
They are computing engines. They (like all NVidia products) just happen to be spectacurly bad at integer math which is what Bitcoin uses. An AMD Tesla equivalent would be awesome for mining but AMD has no such product.
They are awesome for what they are intended to be used for .. double precision floating point HPC.
For example NASA recently expanded one of their climate modeling super computers. It has 30K Intel CPU. They added 64 (yeah just 64) Tesla processors and that provided the equivelent computing power as 10K more Intel CPUs.