I just wonder how valid that information is.
Many folks here have arrived on the same visa that your wife will be issue and have not so far applied for any Biometrics card.
As far as I know it's still the case that although Biometrics forms part of the visa application in Philippines there's no card or paper evidence given of that.
UK has a different set of rules on that and application will result in the issue of a Bio card.
Basically you cannot apply for a Biometric Residence Permit unless you are applying to extend your stay in one of the qualifying categories. (ie FLR / ILR )
Those who are not in such categories continue to rely on the visa vignette in their passport.
Anyway your wife will have no problems.
For your own peace of mind please do contact your own Immigration Directorate.
Your feedback here on the information they give would be helpful, especially if, as you have intimated "entering the UK on route to Guernsey and if planning to stay in the UK for a given time before going to Guernsey,biometrics are needed " is correct. This advice seems to imply that those folks arriving to UK on settlement visa's issued in Manila should also have a Biometrics Residence Permit. But none is actually issued.
Sounds a bit confusing really.