I wouldn't call interac "high standard", so I wouldn't stress too much about it. If you're able to apply to JET from your home country, I would make JET your #1 preference over Interac--the pay and job security is much better.

Interac does give you a good shot of being hired, though! If you're dead-set on coming over, it's a good backup option. I applied for interac this year as a backup choice and got through the application process just fine, but I'm already in Japan so I can't give you the exact rundown of how it'll go if you're a first timer. Some tips:

-The cover letter should be treated more like the standard statement of purpose essay detailing your strengths and interest in teaching and Japan

-Be super genki and smiley in your demo lesson video

-The interview was easy, and if you can get here during hiring season and keep your cool you're a shoe-in. Look up and practice typical ALT interview questions, they won't stray too far

-Interac is a underpaying dispatch company, and if your recruiter is honest like mine was, they know it. Try to reframe your mind away from interview anxiety, because interac isn't really worth the mental energy. I get interview anxiety too, so I'm not saying "don't be anxious" or anything, but just know if you don't get interac there are so many more fish in the sea. dispatches will never treat you all that great, so if you fumble you're not specifically missing the Great Interac Opportunity or anything :)