If |deep learning| implies a discreet GPU then battery life will suffer. It will particularly suffer under Linux because the GPU and CPU manufacturers don't have not created Linux drivers that allow dynamic switching between the GPU and CPU graphics core when running the display. The CPU graphics cores generally use less power than the GPU and the switching provides longer durations running on battery power.
A similar tradeoff comes in terms of processing power versus weight and bulk. Fast multicore processors need to dissipate more heat. Heat sinks add weight. Fans require passages to move air and add bulk.
If portability and light weight is the killer feature then there are one set of alternatives. If 64GB of ECC; two teraflop of GPU; and a quad core Xeon are killer features then there are another set of alternatives.