Storing attachments in SYSATTACHEMNTS table of db is legacy approach inherited from SC on P4, it has its pros and cons, but at least for some customers the current attachment's handling method isn't optimal it terms of extensive using of large attachment files within SM modules.
Extensive work with attachments of 30-100M size will generate significant traffic between SM RTE and Database which will affect the performance of routine end user's operations. The other limitation of current design is scalability, for most of customers SYSATTACHMENTS is the largest table in SM Database and it require additional efforts to maintain it properly, - keep separate datafiles, estimate DB size growth per time to have available disk space resources, etc.
One of possible solutions for attachments can be files storing in configurable FTP server but the simplfied infomation (including file storing location) can be stored in DB still.
Same enhancement request is available per this link.