This is a difficult one. Many landlords have mortgage contracts that expressly prohibit this. Believe me, they would if they could - it would broaden the market for tenants enormously.
But let's assume it's the landlord's choice for a moment - why would they say no? HB claimants are not usually a problem, especially if they are working, so they would be considered fairly.
DSS tenants can be an utter nightmare and a huge liability from a landlord's perspective. Even if the rent if paid directly to the LL via the LA so that arrears cannot be run up, the wear and tear, and the sheer hassle is enormous. Places get burnt down, flooded, stacked to the ceiling with shit, the boiler ripped out, the floors ripped up, the copper piping nicked, the gardens trashed and used as toilets, sinks ripped from walls, they get used as crack dens, brothels, they get filled up and overcrowded with subletting illegal immigrants, the address gets a terrible credit rating which can be very hard to shift and can affect the owner directly, the neighbours make endless complaints due to anti-social behaviour, the police are always there, blah blah blah. And no-one wants to give you insurance. And if they do it costs a bloody fortune.
People moan that landlords overcharge for housing, and rip off local authorities to house the vulnerable, but all of the above are factors that people fail to take into account when LLs set their rents for housing 'vulnerable' or high maintenance tenants. There has to be a financial line below which, as a landlord, you will not go - it just isn't worth the hassle, and the risks are too great.
Of course with HB for non-nightmare tenants, I agree, it's a real shame. But the simple fact is that the building societies know from years of experience that HB claimants are statistically less likely to pay their rent regularly and on time than non-HB claimants, and that can lead to the landlord who is highly geared facing repossession.
This could easily be solved if all HB was always paid directly to the landlord, bypassing the tenant, but all the while that is considered to be demeaning and is not standard practice then we are stuck with what we are stuck with.
Incidentally I have an asylum seeker in one of my properties, funded by social services. They've been there 7 months now and I still have not had a penny in rent from the LA, because I am obviously still languishing in someone's in-tray. And I am paying the utilities as well - can you imagine my heating bill for this winter? Luckily I don't have a building society breathing down my neck, or I'd be having to turf him out. which would make me feel terrible, but I am not a charity - it's my job.
Its not always the landlord's fault.