Because marketing tags doesn't seems to be working properly for page variants (personalised pages). (At least this was our issue on corp-web with m6.2.10 - tag which has selected specific page variant where it should be rendered, then it wasn't.).

So I decided to rewrite all logic from java model into ftl. Advantage: it could be easier than for clients to do more adjustments into marketing  tags logic. 

Attached my ftl code.

PS. didn't touch cookie part - not sure about how that one should works.