Caveat: Primarily fighting cities here.
After the changes to the tourney structure, I went back and completed all the optional SS research I had skipped. I didn't do them all at once; I filled them with kp and paused there until an event quest for 'activate a tech' appeared, then used them for that. I still do that when I move through the chapters, the techs are usually activated by chapter end or early in the next chapter now. Map encounters are mostly blue (very easy) now, but that was not the reason for taking those techs. I only do map encounters when called for in event quests; I do way more tourney/Spire encounters week in/week out. The biggest impact for me was on AW rewards. There are AW rewards that are based on SS. Some of these I consider incidental like the troop productions (ex: Bulwark produces Barracks light melee as a percentage of SS) since that is not the primary reason I have for building those AW's. Bulwark was built to drive training size higher to be able to produce something 24/7 even when AFK. It was helpful to use along with the Needles that increased training speed, sometimes to the point where queues would run out overnight, producing nothing for a couple hours. I only took Bulwark to lvl 6, then got Shrooms (same thing but based on armory levels) and upgraded it since I was keeping SS low then because of the old tourney structure. Since catching up on the optional SS techs, upgrading Bulwark is now a good use of my kp. It was identified somewhere that increasing SS makes the troop producing culture bldgs less appealing since their production amounts are based on chapter, not SS. I think that's probably true. I do tend to use the crafted Orc Strat and Vallorian Guard buildings way less now anyway, but I use those troops sparingly as well. And things like the Witch Hut and the Dojo's are probably a less efficient use of space, but I'm keeping those, lol! I find that an acceptable trade-off for having 15hr training queues making 3 squads/training slot. Across all three buildings, that's 72 squads/day to replace lost troops. I don't usually lose 72 squads/day. My personal preferences for certain troops (Merc Camp!) cause the culture bldgs that make those troops to be appealing to me anyway. Every little bit helps, lol!
Edit to add: it was
@BrinDarby (right above me here, lol!) that mentioned the lessened efficiency of the culture bldgs that produce troops.