It would be a good idea? Anyhow I'm wondering from who do have the founds this employer? Who work with bitcoin today? I heard some people in Polonia but I don't know if they continue to do this after the drop of the price of bitcoin. Then when do you find the safety that the price of bitcoin will not go 2 us dollar in your time of retirement. What do you do in this case? I personally don't believe that but who knows the future? Third why don't do this with your fiat money of your country? It is not more secure this? 
For the vast vast majority of bitcoin investors, they would have to use a service that have scheduled transfers/buys to do this.
i.e. Coinbase
With it you can schedule weekly purchases which can be sent to a multi sig vault
Although.. if you use this method, it still takes self discipline to not spend it too soon