Fur Hire's main problem is that they are extremely normal summon reliant. If your normal summon is negated, all a player can really do is pass turn at that point and more then likely lose. The addition of the brilliant fusion engine to the deck helps with that problem by having the potential to give the deck an extra normal summon to fall back on. It also provides two different typed monsters for folgo, (Being seraphinite and trick clown) letting you get into your boss monster fairly easily.
With fur hire's main gimmick being able to swarm the board, one can easily also go into any link monster one's hart desires for any situation. Such as borreload, or borrelsword dragon for OTKs, or the knightmares to out problem cards. There's also a small rank 4 engine in the extra deck for more niche situations.
Finally the side deck is geared almost souly for when you have to go second. The only card in the side deck that's not a going second card is cosmic cyclone. the side is build this way as, while two of the fur hire monsters can pop either a face up card or a face down when a fur hire monster is special summoned to the field, I feel fur hires do not do well going second so this side is made to mitigate that.