Steam Client vs PoE Client?

Some time ago Steam updated longer because the updated data was larger.
You can't use the torrent update file at league start even now.
But with a fast DSL even 10 GB took me some minutes only.

When you have steam overlay active you can buy PoE points easily with your steam wallet.
And steam has other goodies like statistics, news and security.

Most bad about steam is they take 30% from sales.
But PoE is free so that doesn't matter for you.