JKR
lots of people have said this before, but it's worth saying again -
The main reason for buying an Epson K3 printer is for the K3 inkset. It is now an industry standard for permanence, gamut, B/W neutrality, and everyone does profiles for it. If you are making prints for sale, then K3 is the assurance of quality your clients will prefer.
There might be some point to purchasing a CIS and filling it with Epson K3 ink from the large 220ml cartridges for the big printers. But more sensibly, if you want lower ink cost and bigger carts, trade in the 2400 and get a 3800 instead.
Best wishes
John