Imbalanced beauty-charmed baryons Ξ +,0 bc are of great significance to the development of heavy flavor physics. In this work, we study the inclusive weak-annihilation decays of Ξ +,0 bc and their contributions to the Ξ +,0 bc lifetimes. For the calculation of the inclusive Ξ +,0 bc → Xcs decay width where Xcs stands for the sum of the final states with charm number +1 and strange number -1, we work in the heavy diquark effective theory which provides us with a convenient technical tool to construct the operator product expansion. The Ξ +,0 bc is considered to be a superposition of two states with one containing a spin-0 bc diquark and the other one containing a spin-1 bc diquark. It is found that both the Ξ +,0 bc lifetimes and the Ξ +,0 bc → Xcs branching ratios are very sensitive to the bc spin in Ξ +,0 bc . As Ξ + bc has a longer lifetime than Ξ 0 bc and bigger branching ratios of similar decay channels, the exclusive decays Ξ + bc → D * + (→ D 0 π + )K − p and Ξ + bc → D 0 K * 0 (→ K − π + )p are more promising for experimental searches of Ξ +,0 bc at the LHC comparing with exclusive decay Ξ 0 bc → D 0 pK − .