As mentioned above some Counters only measure frequency, while some which are usually called Universal Counters can offer more features which you may or may not need.
For instance if you were designing a system that uses pulses from something like an photo-interrupter, an oscilloscope would easily tell you the frequency of the pulses and this could be used to determine speed. While a Universal Counter could tell you the number of pulses which could be used to determine position, (but of course if the pulse count is low can manually count pulses on the oscilloscope).
Universal counters can also have features like the ability to divide the counts on two of its inputs and display the result. So if you design a system that performs some function each time a pulse occurs, you could use a Universal Counter to verify that your system isn’t missing pulses by changing your system so that it outputs a pulse each time it thinks it has receives one. And then when you use the Universal Counter to divide the input to your system by the output from your system, the counter should always display near enough ‘one’, since any number divided by itself is one, (but the counter may need to be set so that it does large enough counts before performing the divide and displaying the result).