Sure, you can do this if you want! It's your comic. : ) If you update faster on your main website, then that can be a big draw for readers who are impatient, and don't want to wait for the next Tapastic-update.
Tapastic is kind of... sticky. In that Tap-readers tend to stay on Tapastic, because it's convenient. Getting them to transfer elsewhere takes some doing! I do my best with reminding people I've got a Patreon, but it's slow going.
However, while the ad-server isn't functioning at the moment, when it does come back up, you can sign up for the Ad Revenue program, which will generate money in your pockets just by people reading your comic here on Tapastic - assuming they don't have ad-block on, of course. It's not a lot of money, but it adds up! SO there are advantages to posting on Tapastic even if you don't see much reader-transfer elsewhere.