They are not at all same. Bitcoin cash has nothing to do with swiftness and affordability of transactions. Fact that it itself will become slow once overcrowded is undoubtedly true. While lightning network provides a much better solution by compressing the fees and times by a great scale and making BTC ready for mass adoption. But what until it doesn't hits the market? BTC dominance is already under 45% they need to launch it very soon to avoid further questions on the supreme command of bitcoin.
I won't even say lightening network is the best way out if we see of long term. Miners are thinking of making BTC ready for a very long term which means it may be used as a mainstream method of settlement. In such a case its impossible for even lightning network to cater such traffic we need some ultra lightning network for it.