Both photos show the cut-plants which resulted from mechanical devices whether mechanized cutters in Egypt or handy cutters in Mexico. Regardless the place, the same rules apply as long as the weed cutting is done in the presence of fish stocks.
The effectiveness of weed cutting is only achieved when all cut weeds are immediately and completely removed from the water; each un-removed plant fragment has the potential to form a new weed. Also, cut plants left in the water will decay and release nutrients that stimulate future weed growths. Moreover, the plant decomposing would require and use a part of the pond dissolved oxygen use oxygen and can lead to fish stress or even fish kills. This matter becomes more dangerous in warmer temperatures whereas the rate of decay is faster, the requirement of oxygen by fish is higher and the holding capacity of water to oxygen is lower.