It displays the discretionary budges and it quite useful in that regard. However, it does not show entitlements. Given that entitlements such as Medicaid and Social Security make up about two thirds of the total federal spending, this seems quite odd to not include.
The creator of the graph’s explanation for not including these figures is that “Congress has no control over mandatory expenditures”. These expenditures are mandatory in the sense that they are automatically renewed and their numbers altered by formula ever year, with no congressional vote needed to reauthorize them. However, a simple majority could reduce the expenditures on these things to zero.