It's fine to require people to pay for your software. I still think it's a good idea to release at least a basic demo version as open source though. With close

It's fine to require people to pay for your software. I still think it's a good idea to release at least a basic demo version as open source though. With close binary blobs for all I know it could upload all my personal files or delete them for good, drop all database tables, install a backdoor, etc. I don't trust random people on the Internet to run their code on my computer.