The 5-4-3-2-1 scheme is very effective and doesn’t “need” to be performed every day… 3 times a week on a lift will give you enough volume if you train hard. Now, which is more effective, the 5x5 or 5-4-3-2-1 scheme?
Well first of all it depends on your level of development: a beginner will tend to respond better to a 5x5 scheme… not so much because of the volume but more because a beginner is not efficient at maximizing muscle fiber recruitment so sets of 3, 2 and 1 might not create a maximum stimulation.
Now, if you are not a beginner which one is better? Well both are different… the 5x5 scheme might give you a tad more size gains while the 5-4-3-2-1 scheme might give you a tad more strength (which can eventually be used to stimulate more size gains).
The best option is probable to use both in a periodized plan: doing 4 weeks of 5x5 then 4 weeks of 5-4-3-2-1 then 2 weeks of 3-2-1-3-2-1