If you use a chess engine you will win a lot of games against those who don't use a chess engine but you won't get the satisfaction of a game of chess. I used a chess engine for six months. I won a lot of games but my chess progressed not at all.
Long time human-only games develops your solid playing style while engines-assisted games are about clarity of the result only. Well, chess is not boxing. Even world champions lose dozens of games per year. So we need to play by our own head and show constantly strong play not that some of us eager to get 100 of 100. I bet even Magnus Carlsen doesn't get 100 of 100 on his level but he keeps to be on his level, this is the point of the proper training.
There was a player in our club who was of near master strength in correspondence chess back before chess engines were available and he refused to play cc when engines came on the market because of his concern with possible cheating. A shame really because he missed out on a lot of fun. Some opponents may cheat but so what? Best to assume all opponents are honest. He died last year, aged 92 and he played over the board up to the end.
11 years ago I knew a Correspondence Chess Master of Ukraine that had 2400 on ICCF without using any software at all. Well, he played 2250+ in OTB chess as well and was one of the best players in my region...
I reckon that the Correspondence Chess Grandmasters of yesteryear (1950-60-70 such as C.J.S. Purdy , the first correspondence world champion) would most likely not play serious postal chess nowadays.