What is Functionally Important for BOOT &/or Program Drive?

In essence, what type of data & function is most important for a BOOT/APPLICATION drive SSD? I assume that this can be differentiated from a DATA drive SSD, where RESULTS are both read from and written to the drive (including intermediate data). Answering this question then leads to analyzing the appropriate comparative tests of the different SSD's and choosing the one that meets your performance/cost targets.

It would seem to me, that for a BOOT (or Program Drive) SSD, where the OS or the application program software resides (not data per se), that READING (and not writing) is generally the critical function. (?)

If so, then is OS and Program information access (requests) primarily compressible "data," or in-compressible, or generally a mixture of both?
Does accessing this information result in single Que Depth or does it build up and become a high Que Depth drive access?
Is it generally small or large blocks of "data"?
Is it Random or Sequential "data"?

Obviously, access times can also come into play.

In trying to answer my own questions from an expected logic perspective (i.e., w/o actual knowledge), I would think that OS and Program reads would be primarily in-compressible, large block, low Que depth requests to a SSD.

Can anybody corroborate/contradict w/ explanation?
Thanks.