The above statement is only true as of Dynamo 2.5.0. Yes, you will gain some improvement pre-2.5 by not rendering the geometry in the viewport. But the memory is still in use. More info on Github
This is of course not an issue if you are disposing of the geometry. which, in the sample .py above, you are not.
If OP is in a version greater than 2.5 (which they probably are), then no worries. But, I thought it was worth mentioning because I have seen quite a few people make that (incorrect) assumption about python “always” being faster. And I do think ideas like “if I can’t see the geometry it must be faster” contribute to that.