And how exactly you don't need patrol fleets ? There are multiple places around my territory with high trade value going on, so how only 1 habitat covers all of this ?
The habitats cover all my navy cap needs. You get insane value for habitats if you use them as navy generators. You only need 4 of those bad boys to get a staggering 1000+ navy cap, you'd need 26 star fortress anchorages to duplicate that.
I got two or three shipyards and the rest are bastions, not a single anchorage. A bastion with 6 hangars will give 60 protection up to 6 jumps away. They overlap and stack a staggering
928 protection where I need it. I can route 3700 trade value through a system and never worry about patrols or pirates, AND the bastions also serve as speed bumps should an enemy fleet get behind my lines.
This is from an end game save where I wiped out all life and I do have 30 something captured anchorages but they still give less navy cap than 6 habitats. Yes 6 Habitats > 30 star fortress anchorages.
Those habitats still produce ~200 science in each category and ~40 trade value so they're not exactly dead weight.
Once you have taken void born and built your first habitat you should convert all your anchorages into bastions and never look back.