Advantages on using a function generator against a multi-pulse generator by using a 555
If the function generator can produce the 50 Hz signal, then there is no advantage to the 555 timer electrically.

Function generator advantages:

Ready to use, just dial in what signal you want.



555 timer advantages:

It makes you learn about a 555 timer.

If you don't value your time (or your professor doesn't), it's a lot cheaper than a function generator.

It keeps 20 students from fighting over the single function generator.