This really depends a lot of developers prefer using just Roblox studio as itself without choosing to learn any third party applications as they could already master similar models that could be created within blender (something that could be made without using any alternative softwares), however, it’s good to learn it since it’s a free software.
It’s an open source option, blender has decent modeling tools, and interface of you’re willing to learn the workflow around it.
Alternative softwares such as the common option blender I think users use it to create high quality models than you would with just studio itself or something that couldn’t be made in it. If you’re wanting to learn it, I would highly recommend starting out small since it provides you with many tutorials and resources something to take along when just starting out.
If you’re interested in getting into learning a 3D software I think it’s worth it consider learning a program you feel comfortable with. You can create some natural models. Learning how to use a program is only half of it as a beginner, with a lot of practice, and patients you’ll be able to produce some decent things out of it.