One advantage of departing IFR (although it really depends how 'public spirited' you are as to whether you view it as such) is that you do your small part towards funding the LARS service which, as you state, you will take advantage of whether VFR or IFR. At least you are contributing to a service that you may be able to take advantage of. I would suggest it is more appropriate for you to assist with it's funding than British Airways who rarely, if ever, use the service yet, under the present funding formula, end up footing the majority of the bill.
Perhaps, the LARS service itself would be more comprehensive if the charges were set at a realistic level and directed at all those who wish to take advantage of the service or would all those recipients be as reluctant to pay as you?
I find a degree of irony in the fact that you are complaining about the charge yet you are one of the few people who, in the case of LARS, is actually paying for a service that you use!