Different between time frames M30 1H and 4H

I can understand the difference between the extremes 1 minute and monthly charts. But looking at M30 1H and 4H , they are nearly identical. I want to try a new system , but trying on 4H will consume large time on trades. Of course I'll use 1H for exit.

Also why do people trade daily and weekly charts , when they can make more pips from shorter time frames fluctuations?? I saw traders live who make 4-5 opposite trades in E/U and G/U ,while a long term trader is still waiting for his pips.
If you have a good system , why apply it on large time frames??

I consider the larger time frame, the more logical it is.
For example, on M1 one can enter with certain deviation not looking into small details. But on bigger time frame is more serious calculation and therefore it has more sense and logic.
Also, small events have big impact on M1 trading not as much as on D1.

The signals on longer time frames, e.g. daily and weekly are more reliable than hourly and under, mainly due to market "noise". For example it is quite usual for a market close or open to cause a whipsaw movement on lower time frames because of profit taking, large transactions waiting and what have you.

I prefer longer time frames because it makes trade management easier and spreads are a relatively lower percentage of my trades. It is also less stressful because with extended moves of 100's of pips it is possible to use lower leverage on a better risk reward ratio.