Some groups are known for "transcoding" (re-encoding for the sake of it), while others are respected for their "transparent" encodes that look identical to the source while saving space.
Larger files take longer to download and consume more data caps.
BitTorrent relies on a "swarm" health model. Large file sizes degrade swarm health. A 2GB file can be seeded by hundreds of users with limited upload bandwidth. A 60GB BRRIP (common for 4K UHD rips) requires users with fiber connections and capacious storage to maintain availability. This centralizes the distribution network, moving away from the decentralized ideals of BitTorrent.
Historically, file sizes were capped by the physical limits of CD-ROMs (700MB) or DVD-ROMs (4.7GB). As digital distribution replaced physical media for the consumer, these caps evaporated. Without a physical container to constrain the release, encoders prioritized quality, leading to an unchecked expansion in file sizes.
For a 1080p movie, a bitrate between 8,000 and 12,000 kbps is usually the "sweet spot." Anything significantly higher without being a Remux likely contains bloat.