According to the Westminster Shorter Catechism:
Q. What is the chief end of man?
A. Man's chief end is to glorify God, and to enjoy him forever.
In the most general sense, God subjected the Israelites to bondage so as to later free them and bring glory to his name. His name, thus glorified, would attract people to faith in him, bringing them to salvation. Thus his self-glorification is to our benefit. It is a bright light saying: Go this way!
4 Then the Lord said to Moses, 2 “Tell the people of Israel to turn
back and encamp in front of Pi-hahiroth, between Migdol and the sea,
in front of Baal-zephon; you shall encamp facing it, by the sea. 3 For
Pharaoh will say of the people of Israel, ‘They are wandering in the
land; the wilderness has shut them in.’ 4 And I will harden Pharaoh's
heart, and he will pursue them, and I will get glory over Pharaoh and
all his host, and the Egyptians shall know that I am the Lord.” And
they did so. (Exodus 14:1-4)
When God spoke to Moses above, the glorification of His Name was given as the purpose of the events.
God has many purposes for the things He does. The events of the Exodus were for the sake of the Israelites, but also to serve as examples for later generations. The pattern of falling into bondage, crying for mercy, and receiving words from God, a new heart to obey them, and an ultimate harvest of righteousness and personal as well as corporate renewal and peace recurs throughout Scripture. Thus the Exodus is both history and a parable revealing the process of salvation and sanctification.
Another purpose was the salvation of the Egyptians. God showed them His power and that their Gods could not save them. This was an opportunity for them to repent and find the truth - but most if not all Egyptians refused.
Of course as Christians, we see that the Israelites followed (involuntarily) a path through suffering to victory that prefigures typologically the path that Jesus would follow. His family was harassed and forced to flee to Egypt before later returning to the Holy Land. The wandering in the desert that followed the crossing of the Red Sea parallels Jesus' fasting and entering the desert to be tempted by the devil, etc. Numerous additional parallels could be produced, but these should suffice.