Worth is something only YOU can determine.
Your E5700 is a dual core with a passmark rating of 1744 and a single thread rating of 1229.
Games like CSGO are largely single threaded so the single thread rating is most important.
The 4 thread G4560 is an excellent budget processor, but the word is out and it commands a price premium many places.
It has a passmark rating of 5070 and a single thread rating of 1992.
You may find a better value in the G4600 (5410/2070) if the price is right.
ThB250 motherboard and 8gb(2 x 4gb) of ddr4 ram is good.
You will be pleased using a graphics card perhaps as good as a GTX1060.
The nice thing about a entry level lga1151 build is that it can be upgraded all the way to a I7-7700K.