Is an (n+1/4) wavelength transmission line impedance transformer comparable to a 1/4 wavelength line of the same composition?
A transmission line terminated in a mismatched load of a given impedance will repeat that impedance every λ/2 (electrical length) back from the termination (e.g. here). You can think of your odd multiples of λ/4 transformer as consisting of a single λ/4 impedance transformer (using the calculations you've already described) plus an arbitrary number of λ/2 sections which repeat the mismatched impedance back to the λ/4 section.
You can use this to make a longer matching section. So your example of DK7ZB's stacked Yagi array is using a 5λ/4 transformer to allow larger vertical spacing of the individual Yagi antennas.
There are trade-offs of course. A longer transformer means higher losses. Multiple sections magnify variations in wavelength so a longer transformer will have a narrower bandwidth. You may be able to achieve operation on harmonically related bands - a λ/4 transformer on 2 m might be usable as a 3λ/4 transformer on 70 cm, if you're lucky.