I work with pilots who either are or have been cadet entry pilots through these schemes, and have done so for many years. For pilots seriously contemplating an airline career at the 250 hour level this is pretty much the only game in town.
I do not work for, nor draw any benefit from any flying school or third party training provider.
If you want me to say that airline employment is likely for 250 hour CPL/IR holders outside of one of these schemes if they just wait long enough, then I am more than happy to do that. However it just isn't true. It never has been, and there is nothing to suggest it will be in the foreseeable future.
The best entry advice is either work your way up to the required direct entry experience levels (typically 2000 hours and 500 hours turbine experience,) or get accepted on to an affiliated cadet programme. If you don't think that is accurate advice, then do what you like. These companies have boxes full of CV's (resumes) that dont meet the minimum criteria, and will never see the light of day. This is simply because they have boxes full of CV's that do meet, and often significantly exceed the minimum criteria, and only a few of these will be considered for second stage interview.
I am not selling you something. I am simply telling you something. If you don't want to hear it, or don't believe it, then that is fine.