Yeah either eurogamer is run by idiots who don't actually know how to play games, or they're taking it extraordinarily out of context.
Rare mods drop all the time. You can buy a random one with in game currency. You never need to spend real money on these.
Legendary mods also drop randomly or you can turn in your horde of rare mods for legendary ones (3 or so of the same rare mod gives you 1 legendary mod) when you hit power 280. I haven't spent a cent on microtransactions and have completed pretty much all endgame content so far without breaking a sweat.
You could run completely without mods and never notice an issue. So, again, silver is pretty much used on cosmetic items. No one buys mods with silver