A custom GPT once set and saved can benefit specific uses, especially for the ability to train it on your data. Writers for example can upload various samples of their work and the GPT will learn the style of the writer, then can use that custom GPT for writing drafts in the style of themselves. But for non-personal data prompts, generic OpenAI ChatGPT, Microsoft Copilot, or Google Gemini will be the most convenient for general use.