I think it depends on how the scheme is set up.
Could be met be HB but only if payment is a condition of tenancy, rather than an optional extra. By your posting, there is an implication that this will be offered, and therefore optional, and therefore would not be eligible under HB regs.
If they make it compulsory, what happens to those people, (perhaps younger and more able bodied) who do not want to pay for this. Will they have to?
If you feel it is a condition of tenancy, it can be met, so long as it is a reasonable amount, and if you think it excessive, you can designate a reasonable amount, and the rest becomes ordinary “rent” to be considered in the normal way. 8)
But be careful – it is difficult for you to give a full and binding answer on this hypothetical situation – as you may say yes, then find some detail, at a later stage which stops you from paying.
I would think hard about giving anything other than a broad, general answer for that reason.