What mounting really does
A mount tool makes a bucket appear as a Windows drive letter. Every app on your machine can then open files from it as if they were local. Behind the scenes, each read and write becomes S3 API calls, translated live.
When a mounted drive is genuinely the right tool
Mounting shines when some other program needs a file path. A video editor that must open footage directly from the bucket, a legacy app that only knows drive letters, a build script hardcoded to a folder. If your job is "make this software see cloud files as local ones," use a mount tool. That is what they are for.
Where the illusion leaks
The filesystem pretends S3 is a disk, but it is not one. Directory listings on big buckets get slow because Explorer asks for more than it needs. A dropped connection mid-save can leave a half-written file with no retry logic. Renames of folders become mass copy operations, because S3 has no real folders. Everything storage specific, from versions to storage classes to bucket settings, is invisible, because a drive letter has no place to show it.
When a real client wins
If the work itself is about the storage, moving lots of data, digging through millions of files, restoring versions, sharing links, managing settings, a client built for S3 does it faster and safer. Transfers get a queue with resume and verification instead of hope. Search is indexed and instant instead of Explorer crawling. Versions, lifecycle rules and expiring share links are right there.
The practical setup
Plenty of teams use both: a mount tool for the one app that needs a drive letter, and a proper client for the actual storage work. If you are choosing one and your work is transfers, browsing and management rather than feeding another program, start with the client.