It's clear Bitcoin Miners are at present earning 6.25 BTC from new block they create and that reward will be reduced to 3.125 BTC from my readings. So how does making BTC scarcer benefit crypto traders generally?
Well, good thing you used you used the word "generally", for this makes answering the question a bit more easier 😅.
The thing is, the scarcier bitcoin is or becomes, the more volatile the market becomes with every buy and sell trade that is executed, and you and I know that, the more volatile the market is, the more it becomes profitable for traders, that is, It becomes easier for traders to trade and make profit in the shortest period of time.
And it doesnt end at the above, scarcity also improves or increases the value of an asset when demand for that asset grows.
So, we can say that, with less number of bitcoins entering circulation on daily basis as a result of the halving, there is the chances that the price of bitcoin will grow significantly from its current levels when more demand for it appears.
I hope this is clear enough.