Your Syfe account can be funded in both HKD and USD. 

As our Syfe Core and Syfe Select portfolios are USD denominated, our broker Interactive Brokers charges Syfe customers a very low currency conversion fee of 0.002% to place trades from their HKD denominated accounts, and this will be borne by Syfe. Retail investors generally pay much more 0.3% in currency conversion fees.

As for Syfe Cash+, please refer to link

If customers transfer funds in USD, there will be no currency conversion fee since our investing currency is in USD for the Syfe Core and Select portfolios.