First, there is no real reason to get an SX OS. If a dongle is your concern, you can get a cheaper (and better constructed) dongle that can be used with any payload.
If you keep your Switch in sleep mode when you're not using it, you're are highly unlikely to need to enter RCM often. Some people who get a dongle, for example, end up only using it when they're at their computer anyway.
A lot of people only enter RCM to remove the SD card or update the system version/CFW. For people who use FTP, it's mostly the latter.