Originally Posted by konfetarius
You are also underselling the invulnerability effect. It is very useful for tower defense, stalling out for cooldowns for duels, and dropping focus + burning cooldowns in team fights. Not having to choose between Deathcap and Zhonaya is actually a very good lategame buff for mages.
If all your self-stasis accomplished is the fight moving away from you, you used it at a bad time.
Correct me if I'm wrong but the duration of the invul is not able to be voluntarily ended early, right? If someone popped that on me in Dom I'd just hop on over to the nearest health pack and thank you for the free advantage for the rest of the fight (which is what most people do in this mode anyway with their stuns; that also happen to have less duration than 2.5). Assuming this was a duel. 2.5 seconds is a fairly long time to give your opponent free positioning considering everyone is generally much more mobility oriented on Dom compared to other game modes and the sheer prevalence of health packs (It's rare to have a battle site where at least one isn't withing a quick dashing range).
If I saw this item on the person defending a tower I just wouldn't assault it solo. It doesn't help against duo+'s because if the one person is enough to force you to burn it then Enemy #2 has had more than enough time to start a tower channel. (And likely 1-2 second's worth of focus on it.) Once it's triggered Enemy #1 can start up his channel; and by the time it ends approximately 5.5 seconds (2+2.5 duration Enemy 2; 1 Enemy 1 after channel is established) will have been drained from your tower.
Unless you have a very wide range AoE (assuming the enemy positions smartly for the cap) it'll take two shots to interrupt them both. By then at least 1 more second of drain will have happened from who ever you didn't hit first; bringing that up to 6.5. A tower only takes 9 seconds to neutralize; the remaining 2.5 will have likely been done by the minion wave pushed up pre-assault.
Yes; there is Garrison to consider in terms of tower regeneration but I personally think it is far more useful to have that 10% MS instead where you can at least attempt to keep a direct channel shut down by poke-and-run tactics. More damage is done to the enemy this way (making it easier for a team-mate to solo clean up if they have to) and stalling longer on your tower than you could otherwise.
I might even go so far to say that particular combo is almost a lose-lose situation. If you pop Garrison pre-Zhon then Enemy #2 will just re-channel while you're stuck being unable to do anything for that 2.5 If you Garrison post-Zhon then that's one more opening for the enemy to finish what they started (reading the enemy SS will telegraph this a mile away; the Enemy #1 has no reason to start a channel and will take the first opportunity to hit you post-Zhon).
That's just my thought line though.