For SWE or other programming/code related positions I can see that making sense. You may only write 30 minutes of code in a day but the other 7.5 hours is spent either cogitating over the problem and creating the environment that allows you to solve the problem or participating in your team to make sure everyone is on the same page.

You split that 8 hours between 2 companies and unless you are significantly under-employed at both jobs (2X in both locations or more) you're not going to be able to give your all.