Tax Assessor and Gold standard are only available after Gov Tech 30. Only Austria and Netherlands get special decisions. And most countries start highly decentralized (usually 3 or 4) and they won't usually use their first slider change for centralization, since a big early revolt before you build up your armies can be really bad. Even if they use every other slider use for the first years (while e.g. the trade slider is also quite important early on) and totally ignore slider restrictions, it will take about 100 years (more when blobbing, less with unifications) to be fully centralized. And then it still only gives you -0.05 inflation/year.
So basically, you're stuck with the -0.1 or -0.12 inflation reduction of a MoM for quite a long time. I wont say you should mint 30% of your income after you got to Gov Tech 30, that's to much for almost any country to be sure. But 20% can be really useful (again, SOMETIMES) and in almost any case, the only thing that gives you that before half of the game (and usually all the important stuff) is over is, well, National Bank.