Need advice regarding learning sap functional

Hi Experts,

I have around 8 years of experience in sap abap. I am now thikning to learn a functional area of my own.

I have worked technically with HR,SD,MM and bit FI.

Please suggest me regarding the module which might be a taken as a technical consultant. Also, which module will have more market value now ?

Will it be more effective to learn BI instead of functional area ?

Thanks in advance.