"Is it worth it?" Depends heavily on what you do, how you approach your photograph and what other equipment you want to use.
If you have a modern digital camera, its value is greatly reduced. When working with a large format film camera, they are invaluable if you want to study the light of the scene carefully before deciding how to take your photo.
A spotmeter is just another method of measuring light and is cooked Help You decide how high the exposure is. In many ways it is not much more valuable than the "Sunny 16 Rule", while in other cases it blows such a primitive "tool" completely out of the water.
The key effect of a spot measurement is to be able to accurately and precisely read a particular part of the image to judge how light or dark it really is, and then compare it to other parts of the image.
However, the same effect can be achieved with a cell phone camera that gives you control over the exposure.
Spot meters are very useful, but they are not magic devices that can improve your photography right away. As with other measurement options, their value is based on a thorough understanding of their function and use.
If you find yourself unable to debate the merits of highlights, midtones, shadows, and blacks should be Even before taking a photo, it is unlikely that you will get a high score with most spot meters. However, if you're reading about topics like the zone metering system [based on Ansel Adams and Fred Archer, not the advanced digital metering modes of some cameras], a spot meter may be your best friend.
Finally, consider your options when it comes to it What Gauge that you buy.
Ideally, you want a 1 degree meter. Wider gauges may be useful, but for accurate, clean work, they may be harder to use and run the risk of producing "muddy" results.
You may also find that a complete solution is not the most effective for you. Personally, I use a small gutter that fits my hand to measure incidents and lightning, and I own an old Capital Digital SP II spot meter that I bought cheaply from a second-hand camera dealer on the Internet. [I think they have fewer "fiddle points" to play around with, especially the Capital Digital, which has two buttons: one to measure the light and one to lock the display if it should flutter …]
It may be a personal setting, but if a meter does not have a scale that lets you see all the aperture and shutter speed options for a particular exposure, it's not a "real" meter.