Simple - more reliable power without ruining the balance and handling.
The 1.4 can deliver 200'ish bhp, more than that requires bigger turbos etc - basically taking the engine beyond it's design parameters.
The 1750 is a lightweight engine from the same stable, so relatively easy to integrate the electronics, with a number of mechanical similarities etc
It starts at 227bhp, so will be more reliable, more powerful and easier to tune if more power is still wanted.