Blockify and most fraud filters work with rules. You choose countries, IP addresses or connection types to block, and on higher plans you block buyers by the details they type at checkout. That works well for known bad places and known bad buyers.
The weak spot is bots that look normal. Bots that use ordinary home internet connections in your own country pass location rules. Skyfense checks how each visitor actually behaves on your store, so it can catch software pretending to be a shopper even when it comes from a normal place.
The other big difference is ads. If you pay Google, Facebook or TikTok for clicks, Skyfense shows you which of those clicks were bots, and what they cost you.