As noted by Intel, support for DDR5 SDRAM memory is one of the main advantages of Alder Lake. To some extent, this is true: the new standard allows processors to demonstrate record performance values. But at the same time, it is necessary to understand that the advantage of Alder Lake lies in the microarchitecture, so it makes sense to use DDR4 with these processors.
That is, most users can easily choose the first option between DDR4 and DDR5. And for the average PC owner, the advantages of DDR5 memory are not yet so obvious that they can justify its cost.