Why are linear bounded automata not as popular as other automata? In my experience, context-sensitive languages and linear bounded automata are frequently skipped or breezed over in computability theory courses, and are even left out of some notable text books, although finite and pushdown automata receive a lot of attention. Surely there must be a good reason for why LBAs are given less focus than their counterparts?
With "appropriate" modifications we can turn these classes into complexity classes; Finite Automata into $NC^1$, CFL into LogCFL, and LBA into PSPACE. 

It should now be quite clear why we are interested in the first two more than LBA. The first two naturally fit into the usual definition of feasible computation. But PSPACE does not.