What are the disadvantages of using a Segwit address?
I do only know one: Claiming
Although they impose quite a huge risk of losing any holdings (i.e. 'newcomers' trying to claim then without any security in mind), they are still very popular.
A few bucks seem to be worth more than security and privacy.
The reason you want to have your BTC on an segwit address is that you have them already there when fees got 'unreasonable' again.
If you still have to move them to an segwit address you do have to pay the higher fee. This fee would be even higher if you didn't consolidate your UTXO's by then.