I am heavily using GSA SER with a lot of my niche websites and ecommerce and I am using articles, web2.0s and engines and it's not limited to blog comments. If you want blog comments you can use better success with XRummer AI. But nowadays I don't even bother with blog comments as GSA still got much better platforms than blog comments articles, networks, and very new goldmines like Woorank, Joomla, WP to NodeBB kind of things which gives real signal.
Don't waste money on indexers instead grab GSA SER with a good link list and you can save tons. And if you are planning to use an indexer use it for the first tiers and no point to use it for lower tiers and spending indexer for a lower tier nowadays costs a lot of money.
My sweet formula is tier 1 from para sites and to get index those para sites which direct to money sites are GSA blasts with do follow contextual engines