Not to mention the battery impact of poorly written javascript SPA's or advertisements.
[1]: https://bugs.chromium.org/p/chromium/issues/detail?id=52663
OTOH there are almost certainly sites that trigger very bad behavior here. While I've never dug into it too much, it wouldn't surprise me that session store was part of why e.g. IRCCloud or Slack have such high power usage (although I don't know for certain -- it could just as easily be something else).
My understanding is that SSD lifetimes concerns are largely misplaced (or at the very least, only relevant for a fairly small subset of users) and that even reasonably old SSDs can handle well into petabytes of writes -- which is far above what this behavior can reasonably approach. But power usage concerns are totally legitimate IMO.
Full disclosure: I'm not unbiased here, I work on Firefox (but have never touched session store).