This will not damage the drum. The bass is elevated for better projection and resonance. If you only play at home then this really isn't something you need to worry about. Elevated basses are most important to the gigging drummer.
many people on this forum will argue that a flatter drum will resonate better. i keep mine flat (the reso hoop is 1/2" off the ground to compensate for the pedal elevating the batter side) and it sounds great.
tilting the drum can offer more upward sound projection, different tom angles, and a different angle for the beater.
More projection? Minimal, if any. Drums are not cannon.
Tilting the front of the bass drum has negative consequences. Because the batter side hoop is held by the pedal, tilting the front up bends the batter side hoop, raising the tension of half the batter head and raising the overall pitch of the drum.
You can prove this yourself. Have a friend raise the front of the drum as you play it. Hear how the pitch goes up as the front of the drum goes up.
Flat is best. The easiest way to ensure the drum is flat is to install the pedal on the front hoop. Adjust the spurs to raise the front by this amount. Reinstall the pedal on the back and you have a level drum that is still off the ground.