It's a big leap from Lay Minister to Licensed Pastor. You may have people who want to keep their secular career for a while longer. For example, I'm too old to begin the process to become a Licensed Pastor, but not old enough to retire and pursue it after retirement.
Actually; your situation is exactly is one of the big reasons FOR the LLP. I know several LLP's, including some I went to licensing school with, who hold secular jobs. One guy is the chief of police of the town he preaches in! If you felt called, and wanted to become a Licensed Local Pastor, and expressed a desire to be bi-vocational and work part-time your DS would probably faint. There's an enormous demand for Pastors willing to serve small part-time appointments. There are also lots of churches who are dying because they are the smallest of a 2 or 3 or 4 or 5 point charge and they don't get much attention from their Pastor. They are often just tagalongs with a bigger to church to help make the salary full-time; but get nothing more than a sermon on Sunday. There are churches out there who would be better served by a bi-vocational LLP than by a full elder who is serving other churches. That's not every small multi-point church; but it's definitely some.
Know that LLP's who are NOT Associate Members (and Associate Membership is voluntary and only an option after completing Course of Study which generally takes 5 years) are not itinerant. While we are still appointed by the Bishop; we are not required to go where sent and because of that, we get a lot of freedom and choice in our appointments that Elders do not. For example, my recent move the DS asked me if I would take a particular appointment; if not I could remain at my current one (I did take the move). If I were an Elder; the DS would have called me and told me where I was going! So if you're thinking you can't be an LLP because the Bishop might move you cross state; that's not the case! The Bishop could ask you to; but he/she won't make you, you can refuse the move. I can almost guarantee the Bishop won't ask. Most bi-vocational LLP's are appointed close to their home and only move if asked; and if they move it's somewhere close.
Bi-vocational Local Pastors is a growing and needed segment in many UM Conferences!
That's sort-of who I am. I am a 3/4 time local pastor and full time student. So my 'other job' doesn't pay (actually I pay them!); but as a Local Pastor my churches understand and accept that I have other obligations, and the DS/Bishop are accommodating as well. That's ANOTHER growing segment; instead of waiting to appoint Pastors until near the end of Seminary (or after Seminary); we're getting appointed in College before seminary! And for the same reason; there's a demand for part-time Pastors (and anyone who is an Associate Member, Provisional Elder or Full Member is guaranteed a full-time appointment; so that leaves us LLP's as the only ones who can be appointed to a PT appointment. Although some Elders in my conference are agreeing to take PT appointments. But they have every right to demand a full time appointment under the BOD)
To the original point; I have a CLM in one of my congregations. It doesn't seem she's utilized any differently than if she were a "Certified Lay Speaker". She fills in for me, and is occasionally called out by the district to fill in other places. She's also our AC lay leader.
As an add, in my conference it's fairly rare for LLP's to get full time appointments unless they have completed or near-completed Course of Study. Although as the Elder shortage continues; that may become less and less true. But at least in the MO conference; the ministry of the LLP is far and wide a part-time appointment.