Some are worth pursuing and some genuinely are not. Anyone who tells you every bite is a case is selling something.
What makes a small bite worth taking seriously:
Where it is. A bite on the face, neck, or hands is valued very differently from the same wound on a shoulder, because permanent visible scarring is assessed separately from the cost of treating it.
Whether it got infected. This is the most common way a minor dog bite stops being minor. Bites drive bacteria deep, and infection frequently appears a day or two later — well after the wound looked fine.
Whether there are nerve symptoms. Numbness, tingling, or weakness can take weeks to declare themselves and can be permanent.
Who was bitten. A small scar on a growing child changes over years, and revision surgery is often staged into adulthood.
What makes one genuinely not worth it: a single puncture that healed cleanly, no scar, no infection, no time off work, and no ongoing fear. If that is your situation, a lawyer should tell you so, and you should be suspicious of one who does not.
The mistake to avoid is deciding too early in either direction. Accepting a quick payment before you know how it heals is a bet against yourself. So is dismissing it and then finding, three months on, that you need a revision procedure and the evidence is gone.
Take photographs now either way. That costs nothing and is the one thing you cannot go back and do. What to capture.