You need a ~lot~ of chips in play to justify breaking out a T100k chip in an event that starts with T25 chips. Generally speaking, at least 600,000 starting chips (so 20 players @T30K stacks or 30 players at @T20K, or equivalent) at a bare minimum, and it's very far from being required or optimal.
20 players at T20K will typically end by the 10000/20000 blind level, but only 400,000 chips are in play -- so at most, a single T100K might be useful but risks negatively affecting playability. Having four T25K chips in play vs that single T100K is certainly preferred.
For 30 players at T30K (600bb), you might see a 30000/60000 blind level, so a couple of T100K chips in play (out of 900,000) could be used, but still much more beneficial to use 8 x T25K chips instead.
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Realistically, you'd want well over a million chips (two million even better) in play before breaking out ~any~ T100Ks. That's four tables of T25K stacks (500bb), or ten tables of T10K stacks (200bb). With no re-buys, typically chip breakdown at tournament end (30k/60k blinds) would be 140 x T5000 and 12 x T25000 (or fewer T5000s and more T25Ks), Replacing some of those T5000s with a couple of T100K chips would leave something like 100 x T5000, 12 x T25000, and 2 x T100000. But I still think it's less than ideal.
With two million chips in play, the blinds get high enough so that T5000 chips are no longer needed, but even then, if you colored them all up with 16 x T100K chips, you'd only have 32 total chips on the table (16 x T25K plus 16 x T100k). Gonna need a lot more T25K chips in play than that, so you're still looking at just a small handful of T100k chips.
Personally, I only plan on using T100K chips (except for the occasional novelty appearance) when stack sizes are T200K and larger using a base-T500 set with a sufficient number of players (20 or more). That's about when a barrel of T100K chips actually becomes useful.