Question

Since machines having $\text{MA}$ less than $1$ need more effort for a given load, why do we even use such machines?

Answer 1

Even though a machine with $\text{MA}<1$ requires more effort for a given amount of load: It offers a gain in speed, i.e., there will be a greater movement of load for a corresponding minimal movement in the effort. Machines with $\text{MA}<1$ are speed multipliers.