Not very practical / secure. Let's go through this, 1) This is a public paste and anyone can access it. If you use dorks/search you'll most likely find it. This is a breach of security for the users which you don't want. 2) Nothing is hashed/secured. 3) People can access the paste by using WireShark (HTTPDebugger & Fiddler won't work for Python) to pull the pastebin link, or re-compile your program from the ByteCode to access the pastebin, and leak the users keys, hwid, etc and so forth. If you're planning on Selling a tool, by all means do NOT use a Pastebin. Use something like auth.gg which is much more secure than a Pastebin. Auth.gg doesn't give you these vulns. Is it free? No, however, you are planning to Sell this tool. So, you're making a profit, investing $2/month for a secure auth. Or you can create your own.
Always confirm via PM before dealing with me.