It's useful to know how many coin tokens were spent.
Of course. Clearly the log should say, for example:
J plays 2 Silvers, 2 Coppers and 2 Coin Tokens
J buys a Province
to avoid any confusion about how the Province was bought. Now where this fits in the priority list among the plethora of things that need to be fixed/improved in the client is a much more complex question. However,
Stuff like this is why the log is necessary (in contrast to people who say the game should be playable without the log) Yeah, if they were watching the UI the whole time, they would have seen the tokens getting spent, but if they tabbed out or sneezed...
is just mystifying. No one's saying you should be forced to play without the log, but if you choose to, even in the cases you cited (tabbing out, sneezing, ...) if you've played Dominion for any length of time (and I'm still a relative newbie) you should realize that if coin tokens are in the game they are a potential source of coinage which are listed by each player's name. And technically, playing with a log is cheating. IRL I can't ask my friend "What card was it that you bought 2 turns ago?" without receiving a tirade. I can't see "What Turn # is this?", etc. Suggesting the game shouldn't be playable without the log, well I just don't get it, sorry.
Now my real idea for a feature request would be to have an audio log, the game announcing things like an opponent IRL would, such as "J is playing 2 Silvers and buying a Noble Brigand." That would be cool.