Reading ORAC' s reply suggests that money was a driver. There would have been a significant engineering cost in maintaining the WE177, they needed regular expensive servicing. Then the cost of security at the bomber bases would also be significant.
To use them in out of area operations, aside from the philosophical argument, would have been difficult. We had only one mounting base - Akrotiri. To deploy to a host nation base could be problematical.
Ship borne deployment would have been feasible using SHAR, the Barriers were not cleared.
The advantage for a sub-strategic system was that HMG could neither confirm nor deny ...
The big disadvantage is that no one would know until it went bang and a tactical launch could attract a strategic response. A better solution would be a nuclear SLCM.