This is the perfect place to post your question. My answer to the question is: it depends on whether you want to farm the rewards given by the L1-4 bosses since the later bosses only have a 50% chance of awarding one item from the same table -and- that table is further diluted by mid-gacha equipment starting at L5. If not, you can probably give them a miss.
When you defeat a Bon Odolida Boss of the specified level, you get one of the rewards featured below.
L1-4 Reward Table
Life Crystal x1
Lv.100 Red Bloom Dragon x1
Lv.100 Blue Bloom Dragon x1
Lv.100 Yellow Bloom Dragon x1
Lv.100 Purple Bloom Dragon x1
Sacred Beast HP Ampy x1
Sacred Beast ATK Ampy x1
Sacred Beast DEF Ampy x1
Lv.100 Red Manyu x1
Lv.100 Blue Manyu x1
Lv.100 Yellow Manyu x1
Lv.100 Purple Manyu x1
Mid-grade Equipment Gacha Seed x1000
Ultra-Pure Ruby x1
Big Teddy Bear x1
Big Slice of Cake x1
Regular Book x1
Normal Pearl x1
Small Teddy Bear x1
Small Slice of Cake x1
Used Book x1
Nazuna's Homemade Cake x1
Equipment Gacha Seed x100
Mid-grade Equipment Gacha Seed x100
Lv.20 Red Manyu x1
Lv.20 Blue Manyu x1
Lv.20 Yellow Manyu x1
Lv.20 Purple Manyu x1
Lv.5 Red Manyu x1
Lv.5 Blue Manyu x1
Lv.5 Yellow Manyu x1
Lv.5 Purple Manyu x1
20000 Coins x1
10000 Coins x1
5000 Coins x1
3000 Coins x1
2000 Coins x1
1000 Coins x1
At random, a 2★ or 3★ character x1 x1
Gacha Seed x100
L5-7 Reward Table, contains all items from the above table as well as below (becomes the bonus table for L8-15 with 50% chance):
Warrior's Ring x1
Warrior's Ring +1 x1
Warrior's Ring +2 x1
Warrior's Ring +3 x1
Warrior's Ring +4 x1
Warrior's Ring +5 x1
Warrior's Ring +6 x1
Warrior's Ring +7 x1
Warrior's Ring +8 x1
Warrior's Ring +9 x1
Warrior's Ring +10 x1
Defense Bracelet x1
Defense Bracelet +1 x1
Defense Bracelet +2 x1
Defense Bracelet +3 x1
Defense Bracelet +4 x1
Defense Bracelet +5 x1
Defense Bracelet +6 x1
Defense Bracelet +7 x1
Defense Bracelet +8 x1
Defense Bracelet +9 x1
Defense Bracelet +10 x1
Defense Necklace x1
Defense Necklace +1 x1
Defense Necklace +2 x1
Defense Necklace +3 x1
Defense Necklace +4 x1
Defense Necklace +5 x1
Defense Necklace +6 x1
Defense Necklace +7 x1
Defense Necklace +8 x1
Defense Necklace +9 x1
Defense Necklace +10 x1
Warrior's Earrings x1
Warrior's Earrings +1 x1
Warrior's Earrings +2 x1
Warrior's Earrings +3 x1
Warrior's Earrings +4 x1
Warrior's Earrings +5 x1
Warrior's Earrings +6 x1
Warrior's Earrings +7 x1
Warrior's Earrings +8 x1
Warrior's Earrings +9 x1
Warrior's Earrings +10 x1