To answer this question, lets first of all see what the author of Colossians is referring to as being "of no value"
See to it that no one takes you captive through philosophy and empty deception, according to the tradition of men, according to the elementary principles of the world, rather than according to Christ. - Colossians 2:8 (NASB), emphasis in bold mine.
And just preceding Colossians 2:23, which you quote in your question:
If you have died with Christ to the elementary principles of the world, why, as if you were living in the world, do you submit yourself to decrees, such as, “Do not handle, do not taste, do not touch!” (which all refer to things destined to perish with use)—in accordance with the commandments and teachings of men? - Colossians 2:20-22 (NASB), emphasis in bold mine.
The author is addressing man-made religious practices in context of asceticism.
Verse 16 requires special attention.
Therefore no one is to act as your judge in regard to food or drink or in respect to a festival or a new moon or a Sabbath day — things which are a [mere] shadow of what is to come; but the substance belongs to Christ. - Colossians 2:16,17 (NASB), emphasis in bold mine.
The list of festival, new moon, and Sabbath day show that the verse is clearly in reference to judaic practices. Besides this we find the mention of meat and drink. All of this is called "a shadow of Christ". So what is he talking about here? Man-made traditions are never a shadow of Christ, hence those can be excluded as being the reference here. Food or drink can also not be reffering to the Kosher laws in Leviticus 11 since there are none applying to drink. The only reasonable explanation we are left with is food and drink offerings prescibed under Mosaic law. Here we have verses such as:
It shall be the prince’s part to provide the burnt offerings, the grain offerings and the drink offerings, at the feasts, on the new moons and on the sabbaths, at all the appointed feasts of the house of Israel; he shall provide the sin offering, the grain offering, the burnt offering and the peace offerings, to make atonement for the house of Israel.” - Ezekiel 45:17 (NASB)
and to offer all burnt offerings to the Lord, on the sabbaths, the new moons and the fixed festivals in the number set by the ordinance concerning them, continually before the Lord. - 1 Chronicles 23:31 (NASB)
See also 2 Chronicles 31:3. The matching terminology between above verses and Colossians 2:16,17 is obvious.
The author of Colossians is making reference to existing Judaic Scripture which has to be taken into consideration when concluding the meaning of this verse. This particular passage cannot be used to support an abolishment of the weekly Sabbath or mosaic dietary laws contrary to as some commentaries have it. Taking into consideration the overall context of the passage as well as the judaic scriptures references by the author, the reference in Colossians 2:16 are the meat and drink offerings on Sabbaths / new moons / fixed festivals, which he calls "a shadow of Christ" in prefigurement. Apart from that he is speaking agains man-made rules regarding the handling, tasting and touching of perishable things.
What the author considers of value can be seen in verse 8, where he writes "...according to the elementary principles of the world, rather than according to Christ." The word "rather" here indicates that, whereas the man-made principles of the world are of no value, the principles of Christ, on the other hand, are of value. Compare vss. 10-17.
Regarding the question if "human will/effort is required at all," the passage is not speaking against discipline in general, but against man-made religious rules as described above opposing the principles of Christ. In fact, the verses following this passage are packed with instructions how we should exercise our will according to Christ:
... But now you also, put them all aside: anger, wrath, malice ... put on a heart of compassion, kindness, humility ... Beyond all these things put on love, which is the perfect bond of unity. Let the peace of Christ rule in your hearts ... giving thanks through Him to God the Father. - Excerpts from Colossians 3:5-17 (NASB)
And it continues with such instructions through most of the rest of the book. Notice the shift from outward religion which is condemned in chapter 2, to the exhortation in regard to the condition of the heart (3:12) and of acts of selflessness and love.