blotunga: Exactly. I can't for example play game A, while the kid plays game B. I'd have to re-buy game B on a separate account.
StingingVelvet: You can install a ton of games on Computer B and then put it in offline mode. Should load all the installed games for a damn long time. I know some report it eventually makes you go online but I spent 5 months in offline mode during overseas volunteering and it never caused an issue.
Three problems with that
First) While may not so much a problem now but impatient 5,6 and 7 (now 7,8 and 9) year old children are not hugely fussy which of the two button they press when the "Stay online" pop up appears
Second) There is absolute nothing stopping Valve from removing or limiting offline mode at a later date. WinStore only allows 1 off line machine, Valve could easily do the same. I've used Steam long enough to have had the rug pulled from under me once, I see no reason they wouldn't do it again.
Thirdly) Valve don't want you to. You'd be breaking the SSA in doing so. Now while they won't send the lawyers, there is a matter of priciple. Valve are clearly saying you can't do something your are legally allowed to do. To me it feels like the "don't ask, don't tell" policy of the military, in that you can only practice a legal right by hidding in broom cupboard and sneaking around.
If there is a Steam game in my library that I or fmaily want to play I'll use Smart Steam emulator, bypass Steam all together. But I'm not going to buy new games bound to Steam.