The question says it all. I am sure they are great for wines that will be consumed young, but what about for wines you are going to store for longer periods of time? Months, years?
FWIW, I made a batch of blackberry blossom mead years ago that took FOREVER to finish fermenting, and after it had been apparently stable for some time, I wound up getting impatient and bottling it when it still had a smidge more of residual sugars than I generally go for. I've always used 1L swing-top bottles, and that time was no different.
Roughly half the bottles were part of a new box of EZ Cap bottles (like these), and half were essentially the same bottles scavenged from store-bought beverages (beer and cider) -- all assiduously cleaned, naturally.
Fast forward three years, and I had the most beeyootiful blackberry-scented champagne. None were flat, and none were bottle bombs.
If you're making flat wine, I can't imagine that the bottles would give you any grief, barring any quality problems with the bottles themselves (like bad or loose spring-tops, as mentioned by dmtaylor in the comments).
The gaskets will last for 10 years or more in my experience, with no loss of pressure or quality, assuming you don't start with terribly degraded gaskets already.
I have no data on this issue. But it seems from other posts you are really cranking out the wine production. I'd encourage you to set aside 10% of your bottles in the next few batches to put in swing tops. Then let us know 4, 8, 12months down the road how the wine is holding up against some traditionally corked bottles.