As it is not considered part of your estate on death, your life insurance payout can be paid out once the death certificate has been issued, without your beneficiaries having to obtain probate. It also gives you great control over where your money goes, as without a trust, your money can be used to pay off any outstanding debts. It is also not subject to inheritance tax.
If you are cohabiting and not married, life insurance in trust can be a huge advantage, as unless your partner has a written a will specifying you are the intended recipient, partners have no legal claim to either the estate or life insurance policy. With trusts, you can provide financial protection for your partner.