Any harm in using other apps during backup?

[JoBoy]

I'd like to do paying work while doing SD! backups to internal HDs and to a Time Capsule drive that I'm not using for Time Machine. If there's no harm in this, it would help me pay the rent. I couldn't find anything on this in the Users Guide and this forum, but I could have missed it. I have a new Mac Pro with four internal drive bays. One is the "main drive" with Sandbox and Macintosh HD partitions. Two other drives are used for bootable SD! copies. The fourth bay is empty. I launch SD! from the Sandbox and want to run my work applications also from the Sandbox. The Sandbox is "shared users" and NOT "shared users and applications."

Also, is there any problem using other applications during a scheduled SD! backup? Thanks in advance.