The "most common intuition" is that if you have a timestamp X, and you add 3600 seconds, you get a same time but in next hour (unless there are timezone shenan

The "most common intuition" is that if you have a timestamp X, and you add 3600 seconds, you get a same time but in next hour (unless there are timezone shenanigans). But that's not true for TAI - it's entirely possible that 3600 seconds after 23:30:00, the time is 00:29:59. No intuition works like that. So that's why I always advocate for UTC, ideally with smeared leap seconds (although this point is kinda moot now). The 0.00000001% of people who actually care about leap seconds can use the library to get TAI.