I guess it matters (to some people) because the upshot is that "older" motherboards and systems will end up being vulnerable and unsupported.
Nope because you asked about whether a TPM bypass was needed for installs on old hardware. Currently only a TPM bypass is required (and the insider release will install on any CPU), but it's irrelevant because based on current details, Old CPUs may be excluded regardless of TPM status with the release version.
BUY NEW! CONSUME MORE! YOUR (perfectly acceptable) SYSTEM (with which you were entirely happy) IS A YEAR OR TWO OLD!
Year or 2 old CPUs are fine - it's the 4 year and over that are currently speculated to be dropped (e.g. 7 series intel released in 2017) - however personally I think it will all be backtracked. no one knows for sure, and it's pointless worrying about it at the moment.
I can't understand why anyone is seriously worried about installing the Insider build on their main machines at the moment anyway - just bypass the TPM/Secure boot requirement and install it on a 2nd machine if you really must play with "new shiny" but honestly it's so rough around the edges, once the new shiny phase wears off, it's a bit of a "what was the point" feeling