Of course, purists should contact the publishers and IFP to let them know that it's really a tetralogy. No Spectre omnibus edition is complete without "Bedtime Story" from TSWLM.
Now this, more than the "Collected Letters", is a cash grab.
Purists would also maintain that Spectre does not appear in YOLT. I'm not bothered by the cash grab, provided it enlarges Fleming's readership. With luck, folks unfamiliar with book Bond will be encouraged to buy this and might be impressed enough to read more, since the Blofeld trilogy is arguably Fleming's masterwork.