first of all you should know that there is a big difference between bitcoin forks such as LTC and bitcoin forks such as BTG.
LTC only used bitcoin's code (forked the code). and also LTC was created so that we can have an alternative bitcoin with different implementation of the technology. for example the algorithm was changed, the maximum number of coins (cap) was changed, the difficulty was changed so that the time between blocks are different,... it is basically a new coin based on bitcoin technology.

but coins such as BTG are copies of bitcoin's code and the blockchain. and they are not changing anything that matters. they usually change something to pretend they did something to make it different and earn money. for example BCH changed block size to pretend solving scaling issue of bitcoin. BTG changed algorithm to pretend making it ASIC resistance, BTP changed the algorithm to pretend it made bitcoin more "anonymous".
these types of forks are more like parasites rather than a real project. otherwise they would have done it like LTC and started from scratch and with a new name instead of abusing bitcoin's brand.

LTC was created because the developers of it wanted these changes in bitcoin but bitcoin could not be changed so they started exploring the alternatives by creating a new coin from scratch. BTG developers wanted to make money so they forked bitcoin and added the large premine to their coin.

these changes are sometimes introducing additional problems which i can't go through all of them here without making this a 10 page comment. you should analyze each on its own. for example LTC change in block time leads to more orphaned blocks and increased size of blockchain. BCH change of blocksize leads to centralization of nodes.