Who uses a thimble?

A seamstress, or a tailor.

Classically, today it's the seamstress and tailor but in actual other fine works were the potential of cutting and piercing the finger it is also used. Very classic thimbles are but mere metal cups that fit over the finger - some are cotts with metal/plastic/or other hard substances. Newer versions maybe all fabric with Kevlar and may be used in fine metal crafting and some jewelry making.

Thimbles are not limited to metal some are very collectible as some version may be made out of sterling silver, ivory, jade, porcelain and even glass.

Some vintage Victorian era thimbles were even decorated with scenes and or gemstones.

In bygone years needle work was a required skill of many ladies to marry there were even ladies finishing schools that did basic needle point samplers as a requirement for graduation. Then thimbles existed in all homes necessity of needle work was due to most clothing was home sewn and store bought ready made clothing a rare commodity unlike today. Plus mending clothing such as darning holes in socks was a very necessary economic commodity. Again as ready made clothing was very costly and labored work the thimble was once common place in every house hold prior to the industrial revolution.