There is a very distinct difference in the types of cutters on sawchains.
semi chisel is a mix between chisel and chipper chains, the corner is slightly rounded, like chipper chains, but the side plate is flat like chisel chain. good for dirty conditions, very good stay sharp capablility. most common besides round chisel.
in full chisel theres two types, round and square filed chisel chain. round chisel is sharpened with a round file or any regular grinder, while square chisel is more efficient and fast cutting chain because it is sharpened with either a special chisel grinder, or a special file. this cutter type has a square corner that allows the top plate to completely sever the wood fibers in one pass. making a faster chain than chipper or semi chisel. best used in clean wood, will work well with clean wood, but in dirty wood it will become dull faster than chipper or semi chisel chain will. still very good for fast working speed and high productivity.
theres also chipper tooth chain, which has a completely round side plate, designed for working in very dirty and abrasive conditions. best stay sharp capability of all cutter styles.
each chain type has advantages and disadvantages, you just need to use the right chain for the job. and keep it sharp.