7th and 14th day are "bundles" which contains if I'm not wrong a few things like keys, (maybe gems) and timeskips.
They don't show like the other rewards as you get only one thing, but you did get it, you just maybe didn't get track of what you had before.

Megacoin is a double-edged sword at high level, yes.
It's a pain when it shows up when you don't want it to; but also, if it cmes at the right time (for exemple, if a showtime dosn't come when you need it), you can also use it as a "second chance" to speed up your run.

But I start to get bored of doing quick runs, it's fast, but really, really repetitive and boring.
And at my point, I need 800 000+ shares to next decoration; or still a lot to upgrade what I currently have...
And well.... I can "only" go for a ~35 000 share run in a couple of minutes; as I don't have the neon sign (bad luck....)

But hey... The neon sign is only +20% share at max level anyway, so not so big loss, I guess...