Investing $2 every week or month seems like a child's play to me I mean how do you intend to increase your portfolio even though Bitcoin investment is a gradual process I don't think I can invest with $2 every week or month because $2 seems like nothing, because of the value of Bitcoin. Investment is not a must, the moment you start it without preparation ( having a stable source of income that will aid your investment well) you might be stranded along the line and we should not force ourselves to invest in Bitcoin simply because our friends are investing when you know within yourself that you don't have the capacity to..., what I am saying in essence is that investing with $2 doesn't make any sense to me.
Starting with the amount you mentioned is not bad as far as thats the financial ability of the said investor since it is not adviseable for us as investors to do dirty jobs or things that are not legal to get funds to invest in Bitcoin but atleast weekly with this amount is ok for the time being until the particular investor upgrades his or her income, am only against any investor settling at his or her starting point with seeking for way to increase his income to enable him or her fasten up his DCA with an upgraded amount that won't also be a pressure on him or her consistently.
In as much as I agree with you that Bitcoin investment is not must, I will also want you to understand that for anyone to even think of starting with the mentioned amount every week or month, it means that if such individual has what it takes to do more of that he will, atleast with that amount it mean such individual have interest in Bitcoin but may be because of financial constraints, I think what such person should be concerned about is consistency and ways to get more income to push up his accumulation amount so that it won't be a childs play as you said your exact word on quote .