because that is not the topic of discussion...and no it will not send any different signal then deploying it in Karachi...in fact that is not how nuclear submarines are deployed...they stay away deep in ocean to ensure any nuclear attack is replied back with interests...
Second bold part is plain stupidity....Just an ICBM brings in sh1t and nothing else...unless and until you are planning to be a world power and want to do proper power projections..and the most important an economic hub of the world to back your raw military....ICBM brings in zero value....