Significantly the BoI Lifeloan is such that if house price inflation is at least 4% per annum (it was 10% compound since 1970) then if the extraction is 30%, in a 15 year period with the rolled up interest ..the pecentage is still 30%. Also crucially, it is time based so if the customer dies in a 5 year period then the interest is for five years.. end of story.. and no 'fixed rate' penalty.
The BoI do not share in any of the uplift and that is the position.
The clear downside is if house price inflation is lower than that or negative.
If the SHIP product is looked at the issue is that the 'today' value of the portion they buy (say worth €100,000) is not what they give the seller. But a percentage. Currently about 47% at age 70. So that would be €47,000. The obvious issue is their share is their share regardless of whether the seller lives for one year or fifty years. And as far as I know there is no 'clawback' to the estate if the seller dies in a relatively short period. In effect this would be 100% 'intersest' in 5 years if the property price did not move at all.
They then 'own' their share and if the value of the house goes up by 50% then their portion is worth €150,000, which is what is paid back. Meanwhile if you took the €47,000 .. it would be a considerable length of time to come near that ..about 17 years.
It is of course true to say that a family arrangement or 'trading down' is financially better. Older people do not want to move. If you are on the state pension, then you survive but dont live really.