Well, we are at a little bit of an impasse when it comes to security now, because of Spectre-attacks.
Theoretical as they well be, depending on your threat model, pondering about their relevance may be... relevant.

Which the Qubes Bulletin (as of Jan. 11) does.

The two key take away messages, as I read them, is: Practice proper VM handling, such as:
1)
Don't run a higher-order security VM in Qubes OS whilst at the same time running a VM that is likely to be exposed to an attack (such as email phishing and spear-phishing).
2)
Get some expert advice if your operational status requires it, or build your own Raspberry Pi cluster. Airgapped.

Finally, it appears to me that the processor in question is doing well on the market: Embedded Security ICs Safeguard PCs and Payments