Yep, that latency thing was a huge deal to Quake(World) players back in the day. ISDN really did give a big (some would say unfair) advantage over "dialup lamers", and gaming was probably one of the main reasons for investing (or maybe more commonly, begging your parents to invest) in ISDN.
Another advantage I don’t think the article mentioned was, of course, the ability for others in the household to use the regular phone while you were online, removing a common source of intra-family conflicts. In the end, though, consumer ISDN remained a transitionary technology and most people skipped straight to DSL or cable.
We used to play Quakeworld and later Team Fortress after hours at our office. A networking consultancy. Where we went through dedicated T1s, multimegabit SMDS on to metro ethernet. We were the LPBs and got accused of cheating constantly, which was kinda true.
Another advantage I don’t think the article mentioned was, of course, the ability for others in the household to use the regular phone while you were online, removing a common source of intra-family conflicts. In the end, though, consumer ISDN remained a transitionary technology and most people skipped straight to DSL or cable.