I understand the cynicism, but the current text of the bill explicitly creates a separate trust which receives the revenue, and is restricted so that:

"The fund shall be used exclusively for the purposes of subsidizing the cost of higher education, early education and child care for lower-income and middle-class residents of the commonwealth."

https://malegislature.gov/Bills/193/H2824

Now, money is fungible so, just like with lottery revenues that are devoted to "education spending" in some states, it could be the case that it won't in fact increase net spending for the designated purpose, since what would have been spent on this purpose will end up being redirected.

On the other hand, the projected tax revenue is so large (>5% of Massachusetts's entire annual tax revenue), that I suspect it would end up being a net increase in funding for the stated purposes, even accounting for fungibility.