HDD’s(Harddisk Drives) are an old technology but still very used to this day, due to it’s cheap costs and high volumes of space, ranging from about 1-14 Terabytes of storage space.
They have two major drawbacks however.
Due to having a mechanical spinning disk inside it, they are generally more prone to failure after about 5 years of regular usage.
They will probably last a bit longer if they are fastened securely inside the case, as they are somewhat vulnerable to vibrations and impacts.
Their read and write speeds will always be inferior to SSD’s as data is written between multiple disks and on different sectors.
This generally means a few more seconds of game loading times or a few more seconds of windows boot times, but nothing really major.
So to sum up:

• Cheap and sizable in storage space
• Only reliable for about 5 years
• Slow in terms of read and write speed