Dosing pumps, 1 vs 2 vs 4 output pump recommendations?

I have started a high tech tank with a powerful light after a break of many years. Dosing pumps like the one by Chihiros are looking really affordable these days compared to the last time I was running a tank.

I would probably just be dosing an all in one micro fertiliser but will this limit me in the future if I get a single output pump? It's much more expensive to buy lots of separate single channel pumps than a 4 in 1 pump. What are people using the 4 channel pumps for?