I think the idea was that he could be invoked by his name, but they couldn’t have people going around saying “Jehova” (or whatever) randomly without any cool powers happening, so they made up the rule to discourage people poking holes in their flimsy story.
It’s not that paying for things is bad. The problem is that good software is vital to digital artists’ income, and both purchasing and learning that software is a substantial investment. When a company sells or otherwise enshittifies their software, the artist is then put in a very hard place. Open-source software is the only way to combat that unfortunately likely scenario. By all means, please pay for that software if you can afford to. Doing so subsidizes usage for less fortunate people who may be able to better their situation as a direct result of your generosity.