Cautioning for offences of violence ought to be an exceptional course. Technically, cautions are not convictions though they can sometimes have serious consequences for the individual - e.g. in relation to certain forms of employment. It is therefore important that arrested persons avail themselves of legal advice before agreeing to accept a caution.
On 18th August, the Daily Mail printed an article claiming that a "caution culture" had taken root in Britain - here. However that may be, there is no doubt that the use of cautioning rather than prosecution has increased markedly in recent years. Quite naturally, there are fears that cautioning will continue and maybe increase given the present government's desire to reduce the number of Magistrates' Courts. The Lord Chief Justice's comment is therefore very timely.
Further details about "Cautioning and Diversion" may be seen on the CPS website.