Audience Mismatch: Shorts subscribers have a completely different attention span. If YouTube pushes your 10-minute compilation to your Shorts audience, they will click off immediately. Your CTR and AVD (Average View Duration) will tank, and the algorithm will bury the video.
Monetization Risk: If you compile other people's Shorts without heavy transformative editing (like adding your own voiceover or reaction), YouTube's AI will instantly flag it as Reused Content when you apply for monetization.
Keep your Shorts channel focused on Shorts. If you want to do long-form compilations, start a separate channel and optimize it purely for search traffic.