Some nitro models with an electric start system may also be configured to work with a starter box to provide an alternate starting method. When using the alternate bump start, the automatic glow plug igniter (if eqipped) can't be used so you'll also need a glow starter.
As with the bump start method, having a non-pull start engine means carrying extra equipment -- the electric starter as well as its batteries and charger. The on-board componenents of an electric start system also add a little bit of extra weight -- a concern primarily in serious RC racing.
These videos demonstrate the electric starter method for a nitro RC:

